3gpp evolved packet system and femtocell...

Next-Generation Mobile Networks:

3GPP Evolved Packet System and

Femtocell Technologies

Next-Generation Mobile Networks:

3GPP Evolved Packet System and

Femtocell TechnologiesFemtocell TechnologiesFemtocell Technologies

Dr. Stefan Schmid

Manager, Next Generation Networking Group

NEC Laboratories Europe

Heidelberg, Germany

([email protected])

Keynote at IWCMC'09, Leipzig, Germany, June 2009

Outline

� A Historic Retrospect on the Evolved Packet System� How it all began� The big vision � Architecture study and battles� The reality of standards

� Overview and Status of Evolved Packet System � What could finally be achieved � Core Principles� Basic functionalities/capabilities� Basic functionalities/capabilities� Limitations

� Open Issues and Future Work� IP Flow Mobility� Localized Routing� …

� Prospects of Femtocell Technologies� Is it just a hype?

� Conclusions

2 Keynote on "Next-Generation Mobile Networks" at IWCMC'09, Leipzig, June 2009

A Historic Retrospect A Historic Retrospect

From the initial Vision to a Standard

How it all began …

� Once upon the time …

� Some researchers and standards folks had a VISION

� The mobile industry engaged into the endeavor to

study the “evolution” of the mobile network systemstudy the “evolution” of the mobile network system

� 3GPP System Architecture TSG started a Feasibility

Study in SA1 on “All IP Networks”

2004 2005 2006 2007 2008 2009 2010 2011


Motivations and Drivers (1/2)

“There seems to be a common understanding in the mobile communications industry that the technical and commercial evolution of this industry sector points towards an AIPN.”

User related and social drivers:

� affordable high-speed mobile accessmobile access

� support of diverse mobile network services

� seamless serviceexperience across access technologies

� ability to obtain low-costlow-end services and high priced high-end services


Motivations and Drivers (2/2)

� Drivers from a Business perspective:

� handle large volumes of IP traffic in a cost effective manner

� support user-to-user and user-to-multicast traffic

� incorporate non-3GPP access technologies with minimum impact

� interworking with other networks (considering � interworking with other networks (considering mobility, security, charging and QoS)

� account for fixed/mobile convergence issues

� Drivers from a Technology perspective

� significantly higher data rates to end-users

� multiple radio access systems


The All-IP Network Vision

Common IP-

based network

Support of a variety

of Different access

technologies

Advanced mobility

management

Session

management

Enhanced Services Enhanced network

performance

Network

extensibility

composition

Security and

Privacy

functionality

QoS Terminal and User

identification

PSTN

AIPN

External IP

Networks

e.g. Internet

End to End QoS Guaranteed Connection

I-WLANOther Accesses

Future Radio

Access Systems

Existing 3GPP

access

technologies

Session

mobilityTerminal-

mobility


The BIG Vision ...

Common IP-

based Network

Common IP-

based Network

Multi-AccessMulti-Access

Terminal MobilityTerminal Mobility

Security &

Privacy

Security &

Privacy

New and

enhanced Services

New and

enhanced Services

Session MobilitySession Mobility

QoS SupportQoS Support

Personal Area

Networks

Personal Area

Networks

Moving NetworksMoving Networks

Network

Composition

Network

Composition

Self-

Management

Self-

Management

Machine-to-

machine

Machine-to-

machine


From the Vision to a Standard

� Feasibility study (TR 22.978) concluded with the All-IP Networks

vision and recommended normative work

� SA1 continued and standardized the “Service Requirements for

the All-IP Network” (TS 22.258)

� Radio Access WGs in 3GPP started with a long-term

evolution of the 3GPP Radio Access Network

� LTE (Long-Term Evolution) == E-UTRAN (Evolved UTRAN)

2004 2005 2006 2007 2008 2009 2010 2011

� LTE (Long-Term Evolution) == E-UTRAN (Evolved UTRAN)

� System Architecture Evolution work for the 3GPP Evolved

Packet Core started (TR 23.882)

� SAE (System Architecture Evolution) == EPC (Evolved Packet Core)

Start of All IP

Networks Study

TR: Technical Report

TS: Technical Specification


System Architecture Study …

� Objectives:

� address architecture impacts stemming from All-IP

Network study (TR 22.978)

� define Evolved Packet Core (EPC) for LTE

� support mobility between heterogeneous

access networks, including service continuityaccess networks, including service continuity

� Architecture work was taken very seriously by the

industry

� number of people involved increased noticeably

(just in the meeting 100-150 people for SAE)

� politics of stakeholders’ interests came into play


The Reality of Standards

Interworking with

Legacy

Actual service

needs

Other

Standards

needs

Time

constraintsTime pressure

Vendor

Interests11 Keynote on "Next-Generation Mobile Networks" at IWCMC'09, Leipzig, June 2009

GERAN

UTRAN

GPRS Core

PCRF2 HSS

Gi+

Gb

Iu

Internet Gi

Architecture “Battles” – Example 1

GERAN

UTRAN

SGSN

PCRF1

Gn/Gp

Gb

Iu

May 2005

“Layer-2 like”“Layer-3 like”

Architecture A Architecture B

Based on IP-

based Mobility

Protocols (IETF-

based)

Evolved Packet Core

WLAN3GPP IP Access

AAA interface

Wi+ Internet

Gi

Evolved

Access

Evolved RANGi

Gi+

Wi

Gi

Op.IP

Serv. (IMS, PSS, etc…)

Inter-AS MM

Evolved RAN

WLAN3GPP IP Access

Evolved Packet Core

Op.IP

Serv. (IMS, PSS, etc…)

PCRF1

R1

Gx+

Gi

HSS

AAA interface

R2

Internet

Wi

Gi

“Layer-2 like”Inter

AS MM

Mobility between

access networks

based on 3GPP

protocols (e.g. GTP)

Evolved Packet Core



December

2006

S2a/b

SGi

hSAE GWMobility

Anchor

(PMIP)

GTP vs.

IP-based

S8b

S2a/b

SGi

MME UPE

non-3GPPlegacy

S2a/b

S8a

HPLMN

VPLMN

S5

(GTP or PMIP)

vSAE GW

(GTP) (PMIP)

PMIP: Proxy Mobile IP

GTP: GPRS Tunneling Protocol

(PMIP)IP-based

Mobility



December

2006

S2a/b

SGi

hSAE GW

“The Compromise

Proposal”

(PMIP)

S8b

S2a/b

SGi

MME UPE

non-3GPPlegacy

S2a/b

S8a

HPLMN

VPLMN

S5

(GTP or PMIP)

vSAE GW

(GTP) (PMIP)

PMIP: Proxy Mobile IP

GTP: GPRS Tunneling Protocol

(PMIP)


From the BIG vision to the

small reality

� From a Core Network perspective, the All IP Network

vision resulted primarily:

� “GPRS Enhancement for E-UTRAN” (TS 23.401)

� “Architecture enhancements for non-3GPP

2004 2005 2006 2007 2008 2009 2010 2011

accesses” (TS 23.402)

� Conclusion of Architecture Study and start of

normative Standardisation work for EPC

Start of

Architecture Study

Start of All IP

Networks Study


First Release of Evolved Packet

System (EPS)

� First release of …

Evolved UTRAN + Evolved Packet Core

= Evolved Packet System

… was standardized in 3GPP Release 8

2004 2005 2006 2007 2008 2009 2010 2011

… was standardized in 3GPP Release 8

� Official freeze of architecture work for Rel-8 was in

June 2008

Start of

Normative Work

Start of

Architecture Study

Start of All IP

Networks Study


Rel-8 EPC ~ Rel-9 EPC

� Not surprisingly, 1st release required a lot of “bug-fixing”

to make it finally work

�Until freezing date of Rel-9 (June 2009), many

essential corrections and enhancements had to be

done still for Rel-8

2004 2005 2006 2007 2008 2009 2010 2011

done still for Rel-8

�Rel-9 is with few exception identical to Rel-8

Official architecture

freeze for Rel-8

Start of

Normative Work

Start of

Architecture Study

Start of All IP

Networks Study


Mission accomplished ?!?

� NEC’s target for the Evolved Packet System (from 2006)

CorporateCorporate

IMSIMS

PSTNPSTN VoIP NWVoIP NW

InternetInternet

SAE GWSAE GWEvolved Evolved

Packet Packet

CoreCore

SAE GWSAE GW

Keynote on "Next-Generation Mobile Networks" at IWCMC'09, Leipzig, June 200918

WLANWLAN

DSL/Cable ModemDSL/Cable Modem

GPRSGPRS

GERANGERAN UTRANUTRANLTELTE

WiMAXWiMAX

MME/UPEMME/UPE ePDGePDG

xGSNxGSN

aGW/aGW/

ePDGePDGASNASN--GWGW

Mission accomplished ?!?

� Finally achieved solution …

CorporateCorporate

IMSIMS

PSTNPSTN VoIP NWVoIP NW

InternetInternet

PDN GWPDN GWEvolved Evolved

Packet Packet

CoreCore

(EPC)(EPC)

PDN GWPDN GW


WLANWLAN

DSL/Cable ModemDSL/Cable Modem

GPRSGPRS

GERANGERAN UTRANUTRAN LTELTE

WiMAXWiMAX

ePDGePDGSS--GWGW

SGSNSGSN

aGW/ ePDGaGW/ ePDG

(EPC)(EPC)

aGWaGWMMEMME

NEC’s Objectives

� Objective 1: Evolve the 3GPP System towards a Common PS Core for any type of access system

� NEC’s vision is to target the EPC as the common core for WiMAX, CDMA2000, TISPAN, … i.e. any future NG(M)Ns

� With IMS (together with all its features) as the common service platform for both fixed and mobile networks �


� Objective 2: Allow smooth and timely migration from existing GPRS Core Network – according to each operator’s needs

� Flexible architecture needed in order to account for diverse operator requirements (e.g. support a standalone PDN-GW)

� EPC should allow easy accommodation of current systems – the “burden” for interworking should be on the new system �

But at a high price!

NEC’s Architectural Principles

� Principle 1: Aim for common, access-independent protocols for authentication, mobility management, etc.

� Key for a common packet core for future NG(M)Ns

� Enables easy accommodation of any new (radio) accesssystems (� future proof)

� Principle 2: Offer seamless mobility among heterogeneous access systems, i.e., WCDMA, LTE, CDMA2000, W-LAN, WiMAX, etc.

�

�


WiMAX, etc.

� Enable operators to deploy or integrate new/different access networks

� Allow operators to maximize their coverage and always offer best access speeds to their subscribers

� Principle 3: Define a new, access-independent roaming interface

� Convergence towards a common roaming interfaces for different SDOs (a single roaming interface)

� Harmonization achieves cost reduction and allows for new, “converged” services across domains

�

�

�

The Evolved Packet CoreThe Evolved Packet Core

Current Status and Business Prospects

Evolved Packet Core

�Basic Principles

�EPC Architecture

� for 3GPP accesses

� for non-3GPP accesses

�Current Limitations

�New Functionalities

�Expected Deployments of LTE/EPC


Basic Principles

� EPS designed to be purely a packet switched system

� IMS targeted as voice service platform

� EPS for 3GPP accesses similar to GPRS Core,

but more “flat”

� Reduction of nodes in user plane path: 4 �� 3 nodes

� GTP remains main protocol for 3GPP accesses� GTP remains main protocol for 3GPP accesses

� EPS enables interworking with non-3GPP accesses

(WLAN, WiMAX, CDMA2000, …)

� IP Mobility between 3GPP accesses and non-3GPP

accesses based on PMIPv6 (Proxy Mobile IPv6) or

DSMIPv6 (Dual-Stack Mobile IPv6)


EPS for 3GPP Accesses

� PDN GW: IP address allocation, charging and enforces QoS

� Serving GW: Local mobility anchor for intra-3GPP HO

� MME: Mobility management entity for intra-3GPP mobility, paging, authentication, bearer management, etc.

� PCRF: QoS and charging rule provisioning

UTRAN

HPLMNVPLMN

3GPP

Access

SGi

S1-MME

Operator's IP

Services(e.g. IMS, PSS etc.)

S10

PCRF

Gx Rx

UE

LTE-Uu

S11S5Serving

Gateway

PDN

GatewayS1-U

S12

S3

SGSN

S4

GERAN

GTP Interface

MME

S6a

HSS

GTP or PMIP Interface

E-UTRAN

PCC Interface


EPS for non-3GPP Accesses

SGi

PCRF

Gx

HSS

Operator's IP

Services

(e.g. IMS, Internet)

RxGxc

S6a

3GPP

Access

Serving

Gateway

PDN

Gateway

SWx

Gxa

� Serving GW: Bearer binding

� PDN GW: Inter-access

system mobility anchor

� ePDG: Security GW

for untrusted acesses

HPLMN

Non-3GPP

Networks

S5 Access

Gateway

(MAG, BBERF)

Gateway

(LMA, PCEF)

S2b

SWn

Untrusted

Non-3GPP

Access

UE

SWu

ePDG

(MAG)

PMIP Interface

PCC InterfaceAAA Interface

S6b

SWm

SWa

3GPP AAA

Server

STa

S2a

A-GW

(MAG,

BBERF)

Trusted Non-

3GPP Access

No GTP bearers!No GTP bearers!No GTP bearers,

only PMIPv6 tunnels


Current Limitations

� No dynamic QoS control for un-trusted non-3GPP

accesses

� No optimized Handover between 3GPP and WiMAX

accesses

� For operators without IMS, voice calls handled in legacy

access networks access networks

� CS Fallback (UE “falls back” to 2G/3G to carry out

voice calls)

� For legacy access networks without IMS/PS voice support,

IMS voice calls need to be “translated” into CS voice during

HO from LTE to 2G/3G

� Single Radio Voice Call Continuity (IMS voice � CS

voice)


Inter-Access System Handover

PDN

GWUENon-3GPP

Access GW

3GPP AAA

Server / HSS

Serving

GWIMS

1. UE discovers and

decides to attach to

non-3GPP Access

IP Connectivity

PCRF

PMIPv6

TunnelVoIP Access Bearer

Default Access Bearer

3GPP access

��2. Attach

8. Proxy Binding Ack

6. Proxy Binding Update

3. Access Authentication 3. Authentication and Authorization

4. QoS Setup

7. PCRF update due to

RAT change

9. L3 Attach

Completion

5. Preparation of

QoS Bearers

IP ConnectivityVoIP Bearer

Default BearerPMIPv6 Tunnel

��

non-3GPP access


Access Network Discovery and

Selection Function (ANDSF)

`

� ANDSF provides to mobile terminals:

1. Access network discovery information: a list of access networks

available in the vicinity of the terminal

2. Inter-system mobility policies: rules that help the mobile terminal to …

(i) decide when inter-system mobility is allowed

(ii) select the most preferable access technology

S14

S14 H-ANDSF

UE V-ANDSF

3GPP IP Access or Trusted/Untrusted

Non-3GPP IP Access

VPLMN

HPLMN

(ii) select the most preferable access technology

or network

� Supports both information

pull and push modes

� Information/policies

provided are fully

operator configurable


Service &

Applications

Internet

Evolved

Packet Core

Overall Evolved 3GPP System

Applications

PCRF

MME

S/P-GW

S/P-GW

Firewall

DNS

SDP IMS HSS

Example based

on NEC Products

Packet Core

Transport &

Backhaul

Evolved

Radio Access

User

Terminals Terminals

LTE FemtoeNB

Micro wave transport / Optical

Router

L2/L3 SW Aggregation SW

MMES/P-GW

Border

GWTo other networks

DNS


� Majority of mobile operators are strongly committed to

deploy LTE and EPC as their Next Generation Mobile

Network

� Incl. most 3GPP2 operators (e.g. Verizon, KDDI, …)

Expected Deployments


Source: ZTE TECHNOLOGIES, vol. 11, no. 2, 2009

Open Issues and Future Work Open Issues and Future Work

Opportunities for further research

Open Issues and Future Work

�Ongoing Developments (to be completed in Rel-9)

�PDN access from multiple interfaces

�Emergency Communications

� Future Work

IP Flow mobility � IP Flow mobility

� Localized routing

�Seamless dual radio handover

� Local IP Access from Base Station (NB)

�…


IP Flow Mobility

Main Objectives:

� Enable dynamically routing of IP flows over specific access networks

� User and/or operator controlled

Proposed Solutions:

� Network based Mobility (PMIPv6)

� Enables operator control

� Requires out-of-band signalling between Mobile Terminal and NW

EPC/IWLAN Mob

3GPP

Non-3GPP

IP Flow 3 (e.g. VT2)

IP Flow 4 (e.g. p2p download)

IP Flow 1 (e.g. media sync)

IP Flow 2 (e.g. VT1) Access

Access

UE

UE

between Mobile Terminal and NW

� Client Mobile IP (DSMIPv6)

� Limited to user control

Benefits:

� Flexible flow distribution

� Load balancing / bandwidth aggregation

� Facilitates resilience

Current Status:

� Feasibility study started

� Target Release: Rel-10


Flows from same application (e.g. V

IP Flow 5 (e.g. IPTV)

EPC/IWLAN Mob

3GPP

Non-3GPP Access

Access UE

UE



IP Flow 1 (e.g. media sync)


Flows from same application (e.g. V

IP Flow 5 (e.g. IPTV)


Localized RoutingProblem Statement:

� Current PMIPv6-based EPC architecture tunnels all user-plane through the PDN GW (Local Mobility Anchor)

� Highly inefficient use of core network resources

� Scalability issues at PDN GWs

Solution:

� PMIPv6 Localized Routing allowsuse of a direct routes between mobile terminals’ Serving GWs

PDN GW

(LMA)

PDN GW

(LMA)

AAA Server

User A’s Mobility

Anchor

User B’s Mobility

Anchor

Access Authentication

Mobility Session Authorization

Address Delegation

Sub-optimal path

Forwarding LoadForwarding LoadOffload traffic !!!


mobile terminals’ Serving GWs

Benefits:

� Avoid unnecessary waste of core network resources (� efficient transport)

� Enables traffic offload at PDN GWs(� increase scalability)

� Reduce of end-to-end delay

Status:

� Ongoing work in IETF WG NetExt

� draft-liebsch-netext-pmipv6-ro-ps-00.txt

User A User B

Mobile A Mobile B

Serving GW

(MAG) Serving GW

(MAG)

Communication

Localized Routing

Path

Seamless Mobility for Dual-Radio

HandoverProblem Statement:

� Current PMIPv6 lacks support for seamless dual-radio handover

� Why? Downlink “path switch” is triggered before radio+access bearer setup is completed

� undesirable delay and jitter

Solution:

� PMIPv6 Transient Binding extension


� PMIPv6 Transient Binding extension(allows completion of radio+accessbearer setup in target access before path switch)

Benefits:

� Low complexity (extension of PMIPv6)

� Enables seamless mobility for dual-radio handovers

� Enhances user experience

Status:

� Ongoing work in IETF WG MIPSHOP

� draft-ietf-mipshop-transient-bce-pmipv6-03.txt soon ready

Prospect of Femtocell TechnologiesProspect of Femtocell Technologies

– Is it just a hype? – Is it just a hype?

Introduction

� What are Femtocells?

� low power access points

� in licensed spectrum

� high speed access (HSPA/LTE)

� cost-efficient backhaul (via customers own DSL, cable, …)

� extension of mobile operator macro cell coveragemacro cell coverage

� with full operator management

� self-organising, self-managing, etc.

� … at low prices

� Where are they deployed?

� Residential

� Enterprise

� Hot spot

38

Residential Femto

Network Architecture


Source: S. Saunders, Chairman of Femto Forum

7 Reasons why Femtocell Technology expected to be successful

1. High spectrum efficiency

� Small cell size, less interference, few users

2. Seamless user experience

� Same terminal, same radio, same service as in macro network

3. Support for legacy terminals

� User benefits without need to buy new terminals

4. Cost-efficient solution for coverage inside buildings4. Cost-efficient solution for operators to provide coverage inside buildings

� Increase coverage depth in buildings through macro cell is very costly

5. WiFi-like solution for high-speed network access at home and in “hot-spots”

� Customer operates equipment, support for LIPA, little impact on MO NW

6. Opportunity for Mobile Operator to offer services in the customer's home

� A “portal” to home-based services and automation and also new

converged services possible

7. Allow for interesting new, location based services

� Great opportunity for new services based on mobile presence in the

home (e.g. child-tracking, mobile advertisement, …)


Open Issues and Future Topics

� Open Issues (already under investigation):

� Seamless hand-in (handover from macro to femtocell)

� Still to be resolved as part of 3GPP Rel-9

� Local (IP|Internet) Access (LIPA)

� Currently be for 3GPP Rel-10

� IMS-based Femtocells

� Hot topic in Femto Forum and 3GPP Rel-10

� Femtozone Services � Femtozone Services

� Enabling new types of home services

� Hot topic in Femto Forum

� Future Topics (opportunity for further research):

� Femtocells based on LTE-Advanced

� Networks of Femtocell for Enterprises and public places (e.g. airport, mall, …)

� Outdoor Femtocells (e.g. stadium, city center, …)

� Mesh-based Femtocell Networks (wireless backhaul)

� Mobile Femtocells (e.g. on bus or trains)


Conclusions

� First release of Evolved Packet System standardized in 3GPP Rel-8

� 4+ years from the AIPN vision to the 1st release of the 3GPP Evolved Packet System standard

� only key aspects of original vision made it into final standard (� still scope for innovation)

� Mobile industry highly committed to deploy Evolved Packet System

� LTE is THE next-generation radio access for mobile operators� LTE is THE next-generation radio access for mobile operators

� Still a lot of scope for optimization and enhancements

� flow mobility

� localized routing

� handover optimization

� etc.

� Femtocell technology has a lot of potential

� Current “hot topic” across the industry

� Scope for innovation (networked femtos, mobile femtos, …)


3gpp evolved packet system and femtocell...

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