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Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion over multiple access networks. With networks evolving into LTE, operators would need to carefully assess the technology fit into integrating complementary nature of multiple access networks into an all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that devices can attach to access end-user services. Communication devices today are able to connect with more than one type of wireless technologies to the “web of things”. An end-user will connect to a Wi-Fi hotspot, if within range. When moving away from range, the communication link is handover to for example, UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely, cellular technologies such as UMTS succeed in highly mobile environments, but limited in bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments and fill up very quickly. The immediate need to curtail congested network and effectively manage mobility is imminent to accommodate the data traffic on their networks. The impact of inter-mobility between inter access technology together with various types of mobility support including 3GPP legacy network and non 3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of supporting real-time packet services. Some of the available IP mobility protocols lack sufficient control to the network to optimize the handover process and do not handle well with slow connection setups of some wireless technologies. This paper highlights the potential approaches of bringing together mobility technologies that are available and how these approaches contribute to resolve operator concerns in deployment of services and combating congestion, access technology integration and evolution to LTE from legacy 3GPP networks.

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Page 1: Mobility Management For Next Generation Networks

USB Dongle HOST-FREE

Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

WHITEPAPER

Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Page 2: Mobility Management For Next Generation Networks

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

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Mobility Management

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1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Page 7: Mobility Management For Next Generation Networks

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Page 8: Mobility Management For Next Generation Networks

USB Dongle HOST-FREE

Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Page 9: Mobility Management For Next Generation Networks

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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Mobility Management

for Next Generation Networks

1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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Contents

Overview 01

Mobility Management, a Closer Look 02

• Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

Mobility Protocols and Standards 05

• Network-based Mobility

- PMIP

• Host-based Mobility

- DSMIP

Greenpacket Smart Mobility 07

Putting Mobility Management In Practice 08

• New Data Services Through LTE co-exist with UMTS

Conclusion 09

Manage Your Moves, in Every Network Seamlessly 10

References 11

Abstract

Increasingly, operators worldwide will be faced with a similar challenge of managing data congestion

over multiple access networks. With networks evolving into LTE, operators would need to carefully

assess the technology fit into integrating complementary nature of multiple access networks into an

all-IP flat architecture. An all IP flat architecture helps to tie heterogeneous access networks that

devices can attach to access end-user services. Communication devices today are able to connect

with more than one type of wireless technologies to the “web of things”. These connections typically

offer the same or similar capabilities (e.g. IP data). An end-user will connect to a Wi-Fi hotspot, if

within range. When moving away from range, the communication link is handover to for example,

UMTS. The motivation of inter-working lies in marrying the diverse strengths of each communication

technology. High-bandwidth data communication inherent in WLAN lacks mobility. Conversely,

cellular technologies such as UMTS succeed in highly mobile environments, but limited in

bandwidth. Although cellular networks are evolving from today’s 3G to LTE that brings promise of

capacity leaps (by nearly 4 times), the overall data growth projection will outpace LTE deployments

and fill up very quickly.

The immediate need to curtail congested network and effectively manage mobility is imminent to

accommodate the data traffic on their networks. The impact of inter-mobility between inter access

technology together with various types of mobility support including 3GPP legacy network and non

3GPP is necessary to provide a target low-latency, higher data-rate, all-IP core network capable of

supporting real-time packet services. Some of the available IP mobility protocols lack sufficient

control to the network to optimize the handover process and do not handle well with slow

connection setups of some wireless technologies. This paper highlights the potential approaches of

bringing together mobility technologies that are available and how these approaches contribute to

resolve operator concerns in deployment of services and combating congestion, access technology

integration and evolution to LTE from legacy 3GPP networks.

Shift of inter-technology mobility is key component in bringing new services to market, closing the

gap on disparate radio technologies to an integrated delivery platform for optimization of CAPEX and

simplifying LTE deployments.

OverviewThe rapid growth of data usage is evident and heightened by the worldwide smartphone shipments increasing by 87.2%1

year on year. The emergence of smartphones, feature phones and tablets are leading the change in transforming the next

generation of user interfaces. Mobile communication has become more important in the recent years. With a service mix

of data, voice, VoIP, IPTV and value added service creation operators are challenged to deliver exceptional user

experience to the end-users. To guarantee user mobility in a cellular network, devices should be able to move seamlessly

in and out of networks. The development of such evolved communication is driven by continuing 3GPP standardization

adopting an all-IP flat architecture in Long Term Evolution (LTE). The IP-based architecture of LTE will evolve towards

Evolved Packet Core (otherwise known as Systems Architecture Evolution, SAE).

3GPP standard defines inter-RAT mobility referring to mobility support between LTE and 3GPP technologies and

inter-technology mobility2 between LTE and non-3GPP technologies. Inter-technology mobility is the ability to support

movement of a device between differing radio access networks.

A basic form of inter-technology mobility can be achieved by a multi-access network enabled device through operator

controlled network selection or user controlled selection. In this case, the device or the user selects which access

network to use and initiates access to it. If the selected access network becomes unavailable, the device selects another

technology, initiate access to it and re-establish communications with the applications again. This basic form of

inter-technology mobility is marginally acceptable for some applications (e.g. email and web browsing) and common for

nomadic users that do not require a high level of QoS. Conversely, in session-based or transaction based applications

(e.g. financial transactions, VPN access, VoIP, video) it seriously degrades the user experience. The process of

re-authenticating onto the network and accessing applications can cause delays and disruption to services. Latency is

not permitted, since this would cause packet loss during the handover period or disrupt the call due to excessive jitter.

For example, a user could be watching video both which may stop during handover.

In order to maintain service continuity, a seamless handover is performed to certain radio performance parameters; delay

constraints in relation to service interruption and the service quality. A seamless handover be it intra or inter handover, is

required by strict QoS and can vary only within a minimal measure, so that changes are not noticeable to the user.

Seamless handover specifications are evolving and in draft development. Within the Internet Engineering Task Force

(IETF) standardization, several protocol variants of Mobile IP (MIP) ranging from MIPv4/v6, PMIPv4/v6, FMIP to HMIP are

already addressing seamless mobility in some aspects at the network and IP level. Additionally, the execution of

seamless mobility together with offloading in consideration, can contribute to less congested networks. The applied

DS-MIPv4/v6 and MIP v4/v6 are commonly adopted in 3GPP architectures (such as iWLAN, ANDSF) in mobility

management and data offloading.

Mobility Management, a Closer LookThe integration between 3GPP and non-3GPP access technologies into the EPC, brings new set of opportunities and

challenges relating to mobility support. The primary need for an IP-based system in cellular communications is driven by

the convergence between telecommunications and Internet in its aim to deliver the Internet and all its services to the

end-users. IP-based cellular system will result in easier and quicker development in integrating multiple access

technologies within a single common IP core architecture which contribute to reduced cost of development for operators

and freedom to choose any access technology without having to excessively overhaul the existing IP core or an IP core

overlay. IP mobility can be adopted to execute inter-mobility standards through various 3GPP specifications. The vehicles

of IP mobility include MIP, DS-MIP, PMIP support.

Mobility management comprise of mechanisms needed to allow wireless devices to move while staying connected to the

radio network, whether homogeneous or heterogeneous. In the simpler term, mobility management primarily deals with

addressing. Devices with multiple interfaces (e.g. UMTS , Wi-Fi, WiMAX etc.) are becoming commonly available and the

set of applications running in the mobile devices is diversifying with some applications run better over 3GPP access

networks (e.g. voice) while some applications run better over complementary - access networks (e.g. ftp transfer via

Wi-Fi). With transition to 4G mobile communication, it is inevitable for better control over radio resource management

(RRM) to complement mobility management methods. It is likely for 3G/4G systems will be characterized by inter-RAT,

IP-based architecture to permit the development of high performance handover. The goal of inter-technology mobility is

highly focused on support in:

• IP addressing in IPv4 and IPv6 flavors

• Network-based and host-based handovers

• Minimized IP core architecture and scalable overlay networks

• Minimized packet losses during handover

• Minimized packet delays

Through mobility management, the inter access network handover process can be further optimized while facilitating

effective offload strategies. Typically, horizontal handover coordinate between two homogeneous networks, handover

within the same network type, e.g. Wi-Fi to Wi-Fi. Vertical handover is the term that describes two heterogeneous

networks e.g. Wi-Fi to UMTS, LTE to UMTS. Handovers in cellular communications typically occurs over data link layer

(Layer 2). However, MIP is often used to allow mobility in the packet data domain i.e. IP layer. The support of seamless

mobility from one access point to another is fundamental in deployment of next generation wireless networks. The suite

of MIP protocol range from MIPv4/v6, DS-MIPv4/v6, FMIP, HMIP. Different flavor of MIP is used to suit differing business

needs and architectures as deemed fit.

Coverage, Economics, and Differentiation toward Multi-Access Wireless Networking

There are many reasons for operators wanting to effectively manage mobility to drive wireless service to new heights.

In the early stage of network build, geographic expansion is necessary. Subsequent to that, operators are seeking to

bundle services (e.g. voice, content, high-speed broadband) for broader coverage to leverage on Wi-Fi. Hence, some

form of marrying offload strategies come into play. In some markets, data demands are already outstripping the

operator’s revenue in excess of backhaul and core network bottlenecks. To ease the capacity constraints and economic

trade-offs, operators are turning to operator-owned Wi-Fi hotspots, metro Wi-Fi hotspots, Enterprise Wi-Fi hotspots and

home Wi-Fi hotspots to deliver content, broadband and applications. Whether it is 3G, Wi-Fi or LTE, a consistent

experience when accessing services, content and the internet is the end-user expectation for ubiquitous coverage

disregarding which access network they are using at a given time.

The benefits of inter-working architecture are clear; however operators need incentive to deploy a new technology with

promise of revenues outweighing the investment. Likewise, users should see tangible incentives to pay for greater

service commitment. Simply put, the end-user should see a significant improvement in their user experience. Given a

case in scenario, a user can access different services (multiple service flows) such as video call, p2p download and ftp

with different QoS concurrently. Based on the operator’s policies in relation to the application and access network, the

routing of IP flows should behave differently. The conversational video call will be routed via 3GPP access, while the delay

tolerant, best effort p2p download can be routed through non-3GPP access (e.g. Wi-Fi) in the presence of multiple

access networks.

Mobility Protocols and StandardsMobile IPv4 was conceived by the IETF and specified in RFC3344 to allow a node within a communication network to

continue using its "permanent" home address (HoA) as it moves around the internet. The Mobile IP protocol support

transparency above the IP layer. Due to the practicality, technicality and business requirements, MIPv4 is less efficient

method of IP data delivery. Mobile IPv6 (RFC3775) introduces mobility support into IPv6. This enables nodes to maintain

connectivity while moving around between different access links. Mobile IPv6 makes it possible for nodes to use the

same IP address on different connections. Mobile IPv6 is well suited for vertical handover as it is a network layer mobility

management (Mobility between IP subnets) that makes it independent of any access technology (link layer).

When designing a handover concept for mobile communication network architecture, the split of mobility functionality

between IP layer and lower layers must be considered – cross layer handover IP based architectures (e.g., link-layer and

IP-layer) to ensure session continuity (make-before-break connection management model) when a subscriber moves

between networks that are roaming3 agreement specific.

From the operator’s perspective, IP mobility management can be statically configured through network-based controlled

handover definition. Dynamic IP mobility configuration can be provided through host-based mobility to devices which

lack upper layer mobility support, by setting up IP routes only to the mobile nodes that undergoes handover process.

This is intended to give sufficient control to the network to optimize the handover process.

When viewed from the end-user, mobility can be interpreted differently. In static mobility, there is zero movement,

whereby devices are connected through wired cable. Nomadic mobility is characterized by the access from point to

point. In case of continuous mobility, of which is already supported by various mobility protocol makes it possible to be

connected and access to network virtually everywhere (only limited by the boundaries of coverage). The 3GPP standards

accommodate the use of Mobile IP (MIP) in combination to support efficient inter-technology mobility. Two basic classes

of mobility protocols commonly practiced in 3GPP architectures include DS-MIPv6 and PMIPv6 which is intrinsically

good fit in the migration from IPv4 to IPv6.

Network-based Mobility

Network based mobility protocols; where mobility is network-based all the mobility signaling is performed between the

EPS network nodes, while the host-client (i.e. UE) is not involved. The advantage of network-based protocols is that

mobility services can be provided to UE that is not mobility aware. It also helps to reduce the amount of signaling and

data tunneling overhead on the radio interface. The downside is that the application of these protocols is limited to

localized mobility and may be hard to implement. One of the commonly used network-based mobility protocol in 3GPP

architecture is Proxy Mobile IPv6 (PMIPv6).

Upon the user leaving the non-3GPP connectivity due to movement of location (mobility), the IP service flow for p2p

download can be triggered to move onto 3GPP access in what is termed as IP flow mobility. (3GPP Release 10 specifies

IP flow mobility). When the user re-enters/enter a location where 3GPP and non-3GPP access is available, the p2p

download is moved back onto the non-3GPP access. All the while, the end-user need not suffer from discontinuity of

services and/or denial due to congestion without major impact in their pricing plans. In cases where users are willing to

pay for premium content, the service commitment is a thrust for operators to retain customers, build loyalty and win back

customers through enabling excellent user experience.

Operators would like to own both the cellular networks and IP networks, but most don’t. The approach in deploying

IP-based network architecture is dependent on the flexibility of existing infrastructure. In simple mathematical terms,

the practicality of deploying IP-based networks should maximize large range and high bandwidth, with minimum cost for

the inter-working. Mobile operators see a gap between bandwidth demand and capacity. The forthcoming LTE/EPC

architecture is anticipated to bring significant changes to the access and core networks that emphasize backward

compatibility. The key goal of flatter, distributed IP architecture is critical to accomplish the convergence and seamless

inter-working between heterogeneous wireless networks.

3 Note: Aspects of authentication, authorization and billing of the visiting subscriber, in relevance to the roaming agreement is not discussed in this paper.

Figure 1: Migration to Converged 4G NetworksSource: Cisco

www.greenpacket.com

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1 Source : International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker (Jan 2011)2 Note: Inter-technology mobility refers to both variants of inter-RAT mobility between LTE-3GPP and inter-technology mobility between LTE-non 3GPP.

PMIP

Proxy Mobile IP is the network controlled layer 3 mobility protocol that is intended at reducing handover latency. Proxy

Mobile IPv6 (PMIPv6) is a network-based mobility management protocol standard that was ratified by the IETF. It uses

the same concept of MIPv6, but operates in the network layer. Proxy Mobile IPv6 tries to offer mobility to IPv6 hosts that

do not have Mobile IPv6 capability by extending Mobile IPv6 signaling and reusing the home agent (emulating the home

network) via a proxy mobility agent. With this approach it is not necessary for the mobile node to participate in the layer

3 mobility signaling.

PMIPv6 provides a solution for network-based mobility management that can avoid both tunneling overhead over the air

and changes in hosts. On the other hand, PMIP can suffer from high handover latency, if the local mobility anchor is far

from the mobility access gateway, thus PMIP is more effectively used in micro mobility management rather than vertical

handovers.

Host-based Mobility

Host-based mobility protocols; all the mobility signaling is initiated by the UE. These protocols provide additional features

than the network-based mobility protocols and can gracefully handle more complex mobility scenarios. As the signaling

and data tunneling are initiated by the UE, there is slight waste of radio resources. There are mechanisms that have been

designed to reduce, if not eliminate, the additional overhead brought on by host-based mobility protocols like header

compression techniques. A host-based mobility protocol commonly supported is Dual Stack Mobile IPv6 (DSMIPv6).

DSMIP

The motivation for Dual Stack MIP (DSMIP) is apparent in mobile networks, where IPv6 is not yet widely deployed. In

such circumstances, mobile nodes will least likely use IPv6 addressing for their connections when they move from IPv4

network to another IPv6 network. DSMIP is designed as access network agnostic, whereby the access network to

which a mobile node attaches to have no implications to the operation of the protocol. Case in point, between roaming

networks in an all-IP network, the TCP/IP layer-2 (data link layer) protocols like Wi-Fi and UMTS shall operate within the

context of an IP layer. The IP layer sits on top of all these access technologies, which means that the protocol that

supports mobility in the network is also assumed to be IP based. Unlike traditional link layer handovers (e.g., those in

cellular networks) vertical handovers take place in different layers according to the level of integration between the

different access technologies.

DSMIP provides a mechanism to use tunneling capability to forward both IPv4 and IPv6 traffic over the same MIP tunnel.

By means of MIP extensions, the mechanism allows IPv4 and IPv6 HoA (home address(s)) binding to an IPv4 CoA

(care-of-address) to continue established connections and maintain the connectivity.

Greenpacket Smart MobilityIdeally, a seamless mobility in the context of accomplishing mobile data offload solution should provide users with a

seamless experience while they use various applications on their devices. It should also make intelligent decisions about

keeping data flows on preferred networks (e.g. retain certain traffic such as VoIP, on 3G/LTE even when Wi-Fi is available).

In encouraging the adoption of mobile data offload, a mechanism to allow seamless handovers between various access

networks (3G, LTE and Wi-Fi) are necessary as such from client-based perspective. Within Greenpacket’s Intouch

Connection Management Platform (ICMP), is a comprehensive client-based solution that encompasses inter-working,

mobility and offloading, which is based on the principles of dynamic policy settings to the device, algorithms within the

device to detect alternative networks and ability to determine the best possible use of available network. Additionally, the

ICMP can be provisioned with preferred hotspots list, that is managed through the Hotspot Manager client to enable

operator to retain their subscribers to stay on the network, by giving the higher access priority to the preferred hotspots.

The ICMP fundamentally improves device and user management by single-client software that converge multiple

network access and executes data offloading transparently through operator defined rules and operator defined access

priorities. Incorporating customizable features and capabilities such as MIP, iWLAN, ANDSF, it further improves security,

mobility and user experience through optimized handovers typical in deployment of high growth real-time data services.

Therein, lies the strength of ICMP in effectively managing the data offloading mechanism. The ICMP is context aware with

built-in Intelligent Client that is capable of configuring connection policies that selects the best network to connect,

ensuring good service quality. The roaming in between networks is transparent to the user.

The framework of algorithms and techniques used for improving system selection based on operator preferences and

local UE conditions/actions consistently across devices is important. A 3GPP standards compliant client-based solution

gives more flexibility to operators and OEMs to define how radios and applications are managed in a multi-radio

environment and steer away from proprietary solutions.

An apparent strength of the ICMP is the ability to offer consistent service across heterogeneous wireless access

networks. By being standards compliant, it provides operators an evolutionary path to 4G inter-working. Operators

looking to data offload can have the assurance of a robust network and eliminate manual intervention on their

subscribers to connect and re-connect when moving between wireless networks. The benefit of backhaul capacity

optimization can be derived from network operational aspects, as well. From the measure of customer satisfaction,

optimized handovers results in fast handovers without causing a noticeable delay and jitter to ensure session continuity.

Figure 2: Greenpacket ICMP

Putting Mobility Management In PracticeInter-technology mobility is described in the following scenario to depict service continuity. Using inter-technology

mobility, new services can be rolled out network-wide in a scalable manner, which targets the efficiency of high traffic

areas, by diminishing the effects of network congestion.

New Data Services Through LTE co-exist with UMTS

An operator with a legacy 3G network requires upgrading and evolving its network to LTE. The deployment of LTE will

be focused in areas of high traffic areas, to support a new suite of over the top applications to satisfy the demands of

subscribers. The operator is conscious in its ambition to cap market position in relation to market dynamics. Although

subscriber’s welcome the new mobile services, they quickly become disenchanted if the promise of service is

delivered poorly.

Realistically, operators need not delay their network upgrade to bring commercial LTE to service. Previously, the operator

would have to wait until the entire network has been upgraded and integrated fully before rolling out its HD video

streaming service. If the service is provided on the existing UMTS/HSPA, capacity restrictions would often make it

unavailable or perform unacceptably in the busiest parts of the network. The ICMP plays an important role in bringing

new services by its intelligent client that is capable of configuring connection policies that selects the best network to

connect, ensuring good service quality through ANDSF. With MIP support, the ICMP maintains service continuity when

switching between access networks seamlessly.

With inter-technology mobility the operator can roll out new services and begin generating revenue as soon as the

network hotspots are upgraded gradually to LTE and co-exist with UMTS. Subscribers can access the service

throughout the operator’s coverage area. In low usage areas, the limited capacity of UMTS/HSPA for video streaming is

enough to satisfy the performance of the service. In high usage areas, the enhanced bandwidth of LTE would allow a

much larger number of subscribers to access the service and/ or a higher quality video stream to be used. It is with

inter-technology mobility and inter-working through iWLAN, users of the service can move between these areas

seamlessly, without noticing the change in access technology and suffer from service disruption. Greenpacket’s ICMP

provides an end to end effective mobility management to operators to match the network resources they have with the

needs of their applications.

SeamlessData Offload

I-WLAN

SeamlessMobility

Mobile IP

AccessNetwork

Discovery

ANDSF

Support for multiple network technologies

and the corresponding multimedia core

network functionality in a multi-access,

multi-service enviroment.BTS

SGSN/MME AAA/HSS

PGW/GGSN

SGW

ePDG

NodeB

eNodeB

LTE

WiFi/Femto/Untrusted

Network

Rel.8S12 — Direct

Tunnel

Rel.8S4 — SGSNS11 — MME

Rel.6/7Gn/GpSGSN

Rel.6/7DirectTunnel

WiFi/Femto/Other

E-UTRAN

GERAN

UTRAN

Internet

IMS

Operator’s IPService Domain

ConclusionGoing forward, mobile operators will continue to evolve their networks to improve the user experience and service

opportunities. The promise of 3GPP Long Term Evolution (LTE) specification is capable of delivering 3-4 times the

capacity increase to networks. However, the additional bandwidth is more of a by-product of incremental spectrum. By

now, many operators realize the finite nature of spectrum. It’s clear that operators need more than LTE to resolve network

capacity in the immediate term. The adoption of alternative wireless technology to complement the existing network

dawns upon several combinations or independent Wi-Fi offloading schemes, inter-working 3GPP and non-3GPP

networks and inter-technology mobility to better manage their resources. As a result, operators are looking for the best

mix of solutions to deliver an optimum user experience and an efficient network.

In 3GPP Release 10 and beyond, there are on-going study and development for better methods to identify frameworks

for finer granularity in aggregation of simultaneous network connections with context awareness. Some considerations

of smart mobility to optimize network resources should address aspects like:

• Fewer network elements towards an all IP based architecture.

• Better routing capabilities to address growing wireless traffic; localized traffic routing to avoid overload on

service provider’s wireless core network elements.

• Dynamic mobility concept, whereby mobile node should be served by the nearest localized mobility

management function and simplified network to lower the cost of connection.

• Transport layer/application layer transparency

Inter-mobility enhancements in MIP technology to recognize different traffic flows can help shape and manage

bandwidth. Notably the desired feature should ideally permit individual IP flows to the same PDN connection to be

routed over different access based on network policy; for example, best-effort traffic may be routed over WLAN while

QoS-sensitive traffic such as voice telephony may be routed only over the 3GPP network with extension of context

awareness. Such features can be characterized at the UE with the ability to move a flow between 3GPP and non-3GPP

(e.g. WLAN/Wi-Fi). This can be done through session intelligence through service flow control, and intelligent traffic

control to dynamically monitor and control sessions on a per-subscriber/per-flow basis as envisioned in next generation

mobility to bring visibility to pricing models. From a commercial perspective, it will bring new promise of offloading

strategies through bundling of data plans onto Wi-Fi/femtocell offload without compromising on the operator’s revenue.

Most operators already operate a substantial amount of Wi-Fi hotpots and services that extend onto roaming

elsewhere. By complementing multiple access network inter-working (e.g. LTE/UMTS/HSPA/Wi-Fi) with mobility and

offloading, operators can derive more revenues and delay immediate CAPEX investment of LTE, going into next

generation networks.

About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember

Manage Your Moves, in Every Network SeamlesslyAs a result of new mobile technologies, people are taking their work and connectivity everywhere. We understand the

mobility, security and financial challenges you face. Our solutions empower mobility to your network while simplifying

mobility management and controlling costs.

Free Consultation

If you would like a free consultation on how you can manage your mobility needs, and improved network performance,

feel free to contact us at [email protected] (kindly quote the reference code SWP0811 when you

contact us).

References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. LTE Roaming guidelines 458_1-31gsma.pdf

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References 1. 3GPP TS_23.261

2. 3GPP TS_23.327

3. 3GPP TS_23.402

4. 3GPP TS_23.861

5. GSMA PRD IR.88 – "LTE Roaming Guidelines" 3.0

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About Green PacketGreenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board

of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur,

Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in

readiness for new markets.

We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications

Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric

multimedia communications services regardless of the nature and availability of backbone infrastructures.

At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade

solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new

demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless

freedom in wireless communications and continuously commit to meeting the needs of our customers with leading

edge solutions.

With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in

4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is

further enhanced by our strategic alliances with leading industry players.

Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX

players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider

in APAC catering to both 4G and 3G networks.

For more information, visit: www.greenpacket.com.

Copyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any form by any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.

San Francisco · Kuala Lumpur · S ingapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong

AssociateMember