1

ALL-IP 4G NETWORK ARCHITECTURE FOREFFICIENT MOBILITY AND RESOURCE MANAGEMENTYOUNG-JUNE CHOI, UNIVERSITY OF MICHIGANKWANG BOK LEE AND SAEWOONG BAHK, SEOUL NATIONAL UNIVERSITY 2007 IEEE Wireless Communications

R96725043 吳家宜R96725011 蔡依珊R96725030 屠敔傑

2

Outline

Introduction on 3G cellular network3G network architectureIntroductions on ALL-IP 4G cellular networkALL-IP 4G cellular network architecture

Pure ALL-IP 4G network Subnet-based 4G network

3

What is 3G access network? (wikipedia)3G is the third generation of mobile phone standards and technology. 3G networks are wide area cellular telephone networks. It enable network operators to offer users a

1. Wider range 2. More advanced services 3. Achieving greater network capacity through improved spectral efficiency Ex: WCDMA, cdma2000

4

Complicated 3G network structure

5

4G introduction4G networks are expected to integrate any kind of wireless network with Ethernet based on all-IP, and become a packet-switching system.All-IP

Exploit IP to integrate circuit switching network and packet switching network into a uniform all-IP network.Every mobile device has a IP.

RevolutionOrthogonal frequency division multiplexing (OFDM) 降低雜訊，增加傳輸量 ( 如 802.11b 屬於傳統單純調變 2Mb/s 和 802.11g 54Mb/s)Multiple input multiple output (MIMO) antennas OFDM 是讓調變波形更複雜，以此來增加電波的資訊含量，而 MIMO 則是同時動用 1 組以上的天線，同時發送多組電波，以增加發送的電波數來增加資訊含量， MIMO 與 OFDM 相同，用 MIMO 技術做為下一個加速提升方案 (IEEE 802.11n)

EvolutionInterworking with existing systems.

6

Converged 4G network

7

4G’s vision

Integrate any kind of wireless network with Ethernet based on all-IP, and become a packet-switching system.To support high mobility

Exploit hybrid multiple access techniques.

To support Data and voice trafficTo increase throughputIntegrated different Quality of Services

8

Mobile IPSource ： http://wnai.csie.ndhu.edu.tw/ITS/news/courseware.htm

Obtain CoA (Care-of Address)

Register CoA for IP updating

Home address

9

Handoff

HandoffWhenever a mobile terminal moves into another cell, it requires handoff to another base station.

Handoff Latency3 phases of a handoff:• Scanning (most time-consuming)• Authentication• Re-association

10

ALL-IP cellular network architecture

The pure all-IP 4G network (2003)The subnet-based 4G network

11

Outline

Network architecture all-IP cellular networkNetwork architecture for efficient multiple access

12

Network Architecture All-IP Cellular Network

Existing cellular networkbase station (BS)• fast power control• wireless scheduling

base station controller (BSC)mobile terminal (MT)

13

4G Network

Functions of BSBS acts the role of an access router (AR)

14

4G Network

Mobile IP (MIP) addresses for handoff

• incur high overhead

hinders from performing smooth handoff

Use high frequency band and result in short cell residence time

latency is a challenging issuefast handoff scheme for address resolution delay

15

Subnet-based NetworkSeparate the functionality of an AR

AR takes L3 protocolaccess point (AP) takes L2 protocol

16

Subnet-based Network

A subnet consisting of an AR and several APsAn MT moving within the subnet performs L2 handoffAn MT moving into another AR area performs L3 handoff

17

ComparisonPure all-IP network Subnet-based all-IP

network

Access network components

AR AP + AR

Operation type Decentralized Centralized

Handoff overhead

High Low

Handoff protocol

L3 L2 + L3

Cost Low High

Advantage Architecture is simple and cost-efficient for implementation

Efficient to resource management

Disadvantage Long handoff latencyHigh signaling

overhead

Architecture is inflexible

18

ComparisonPure all-IP network Subnet-based all-IP

network

Access network components

AR AP + AR

Operation type Decentralized Centralized

Handoff overhead

High Low

Handoff protocol

L3 L2 + L3

Cost Low High

Advantage Architecture is simple and cost-efficient for implementation

Efficient to resource management

Disadvantage Long handoff latencyHigh signaling

overhead

Architecture is inflexible

19

ComparisonPure all-IP network Subnet-based all-IP

network

Access network components

AR AP + AR

Operation type Decentralized Centralized

Handoff overhead

High Low

Handoff protocol

L3 L2 + L3

Cost Low High

Advantage Architecture is simple and cost-efficient for implementation

Efficient to resource management

Disadvantage Long handoff latencyHigh signaling

overhead

Architecture is inflexible

20

Network Architecture for Efficient Multiple Access

Cells are categorized into:Macrocells deployed in rural Microcells deployed in urbanPicocells deployed in building

User are categorized into:High-mobility users (macrocells)Low-mobility users (microcells)

21

Macrocells and MicrocellsMT can access macrocells and microcells

macrocells cover high speed MTmicrocells cover low speed MT

22

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

23

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

24

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

25

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

26

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

27

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services

28

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services e.g., voice

service

29

OFDMA v.s. FH-OFDMA

If an MT can support dual modes, it can switch cells in a manner of using vertical handoff

OFDMA FH-OFDMACombination

OFDM and FDMA Frequency-hopping and OFDMA

Advantages Higher allocation granularity

High spectral efficiencySupport various data

rate by AMC

Exploit diversityHigh mobilityOvercome channel fading and

multi-user interference

Disadvantage

Limited to low mobility Difficult in supporting high data rates and AMC (adaptive modulation and coding)

Mobility Microcells for low mobility Macrocells for high mobilityTraffic type High rate data services Low rate data services e.g., voice

service

30

QoS of wireless access networkIn general, a wireless access network becomes a bottleneck for providing end-to-end QoS.To support IP QoS, the Internet Engineering Task Force (IETF) recommends

integrated services (IntServ) differentiated services (DiffServ)

31

IntServIntServ uses Resource Reservation Protocol (RSVP) to reserve bandwidth during the session setup.IntServ ensures strict QoS, but each router must implement RSVP and maintain per-flow state, which can cause difficulties in a large scale network.

32

DiffServ

In DiffServ, the QoS level of a packet is indicated by the DS field of IP header, so that differential levels of service can be given to different aggregate flows at the entry points to the network.Since DiffServ is not so rigorous as IntServ, it is scalable in supporting QoS statistically.

33

QoS of wireless access network (cont’d)

The importance of unified QoS management grows in 4G networks as QoS management for both access networks and IP networks becomes cumbersome in all-IP networks.

34

QoS of wireless access network (cont’d)

3GPP (third generation partnership projects) define four traffic classes and their related parameters for QoS provisioning.However, direct translation is difficult since access networks have their own QoS attributes that require strict QoS provisioning within them.

35

ITRAS

IP-Triggered Resource Allocation StrategyITRAS concerns the information about IntServ and DiffServ for the resource management of L1 and L2.

Cell type: microcell or macrocellMultiple access: OFDMA or FH-OFDMAMAC channel: dedicated or sharedPHY scheduling: priority or fairness

36

ITRAS (cont’d)

For example, when an MT requests a real-time service, the corresponding AR can initiate IntServ and MAC reserves a dedicated channel.In contrast, when DiffServ is used for low mobility users, MAC can expolit either a dedicated or a shared channel.

37

ITRAS (cont’d)

38

ITRAS (cont’d)

39

ITRAS (cont’d)

There are other issues to be considered

How an AR cooperate with its subordinate AP in performing ITRAS functions.Load balancing in macrocell and microcell.

40

Conclusion

This article discusses a new approach for designing an architecture and QoS model which cover L1 through L3 in 4G network .

Subnet-based cell structureCombine the multiple access schemes with cell selectionUnified QoS strategy