1 Advisor: Dr. Kai-Wei Ke Speaker: Ming-Chia Hsieh Date: 30/07/2006 A Dynamic Uplink/Downlink BWA and Packet Scheduling Mechanism in WiMAX.

1

Advisor: Dr. Kai-Wei Ke

Speaker: Ming-Chia Hsieh

Date: 30/07/2006

A Dynamic Uplink/Downlink BWA and Packet Scheduling Mechanism in WiMAX

2

Outline

Background WiMAX Standard Overview Proposed Architecture Simulation Conclusion

3

WiMAX Overview

WiMAX? (Worldwide Interoperability for Microwave Access)

Wireless broadband network connection technique. Replace last mile. Cost saving Easy to deploy

4

Basic WiMAX Network Architecture

Subscribe Station (SS)

Subscribe Station

Radio tow er

Wireless link

Radio tow er

Radio tow er

Radio tow er

Base Station (BS)

Subscribe Station

Core network

Wired/wireless links

Users

5

Outline

Background WiMAX Standard Introduction

Frame Structure. Generic / Request Header Service Classes. QoS Procedure.

Proposed Architecture Simulation Conclusion

6

Frame Structure

adaptive

Frame j Frame j+1Frame j-1

PS 0 PS N-1

Downlink Subframe Uplink Subframe

N = (Rate x Frame Duration) / 4

7

Downlink subframe

Pream

ble

Broadcast ControlDIUC = 0

TDM DIUC a

TDM DIUC a

TDM DIUC a

Pream

ble

DL_MAP UL_MAP Transition Gap

8

Uplink Subframe

Initial RangingOpportunities

(UIUC = 2)

RequestContention Op

ps(UIUC = 1)

SS 1Scheduled

Data (UIUC = i)

● ● ●

SSTGTransmit/Receive Transition Gap

Access Burst

Collision Collision

BW Request

9

UL/DL MapFrame n-1 Frame n

DL-MAP

ATDD Split

DL-MAP

FrameControl

DownlinkSubframe

UplinkSubframe

UL-MAP UL-MAP

ATDD Split

10

Outline

Background WiMAX Standard Introduction

Frame Structure. Generic / Request Header Service Classes. QoS Procedure.

Proposed Architecture Simulation Conclusion

11

Rsv (1)

Generic MAC header

HT = 0(1)

EC(1) Type (6)

CI (1)

EKS(2)

Rsv (1)LENMSB(3)

LEN LSB (8) CID MSB(8)

HCS (8)CID LSB (8)

(#) number of bits

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Bandwidth request header formatH

T = 1 (1)

EC(1) Type (3) BR

MSB(11)

BR LSB (8) CID MSB(8)

CID LSB (8) HCS (8)

13

Outline

Background WiMAX Standard Introduction

Frame Structure. Generic / Request Header Service Classes. QoS Procedure.

Proposed Architecture Simulation Conclusion

14

Service Classes

UGSConstant bit rate , fixed packet length (ex. VoIP)

rtPSvariable bit rate , variable packet length (ex. MPEG)

nrtPSDelay tolerated (ex. FTP)

BEBest-Effort (ex. HTTP)

15

Outline

Background WiMAX Standard Introduction

Frame Structure. Generic / Request Header Service Classes. QoS Architecture

Proposed Architecture Simulation Conclusion

16

IEEE 802.16 QoS ArchitectureSubscriber Station (SS) Base Station (BS)

Application

Connection Classifier

UG

S

rtPS

nrtPS

BE

Admission Control(undefined by IEEE)

Connection Request

Connection Response

BW Request

Scheduler UL-MAP

Data Transmission

Uplink Packet Scheduling( UPS)

(Undefined by IEEE)

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IEEE 802.16 Procedures

BS SendUL/DL Map

BS SendDL Data

SSs SendBW requests

SSs SendUL Data

BS RunBWA

BS ReceivesBW Req.

SSs ReceiveUL/DL Map

SS ReceiveUL Data

BS ReceivesUL Data

18

Outline

Background WiMAX Standard Introduction Proposed Architecture

Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description

Simulation Conclusion

19

Proposed QoS Architecture

Upstream

BS

Request DB

SSBW Request

BWA

MAP Generator Packet

Scheduler

DL/UL MAP

UGSrtPS

nrtPS

BE

Downstream

Classifie

r

Packet Scheduler

Request Maker

UG

S rtPS

nrtPS

BE

Classifier

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Problem & Solution of BWA

60 50 40 30 20 10

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Outline Background WiMAX Standard Introduction Proposed Algorithm

Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description

Simulation Conclusion

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Request Maker

Request Maker

Connections

CID:001, BW: 100Kb

CID:002, BW: 150Kb

CID:005, BW: 50Kb

Bandwidth request messageSS

BS

Latency CID

60 001

70 003,005

100 002

CID:001, BW 50Kb

CID:002, BW 50Kb

CID:003, BW 50Kb

CID:004, BW 50Kb

CID:005, BW 50Kb

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Request Database

CID : 0011 (UGS)TotalNeeded 7000Kb TotalDelivery 3000Kb

Arrival Time 70 毫秒 100 毫秒 130 毫秒 140 毫秒

Deadline 130 毫秒 160 毫秒 190 毫秒 200 毫秒

Bandwidth 1000Kb 2000Kb 500Kb 1000Kb

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Outline Background WiMAX Standard Introduction Proposed Algorithm

Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description

Simulation Conclusion Reference

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Bandwidth Allocation ProceduresDL

Emg(UGS)

UL Emg(UGS)

DL Emg(rtPS)

UL Emg(rtPS)

DLNEmg(UGS)

ULNEmg(UGS)

DLNEmg(rtPS)

ULNEmg(rtPS)

DLnrtPS

UL nrtPS

DL BE

UL BE

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BWA for Non-Real-time

Sort By Satisfaction rate. Allocate bandwidth from lower satisfaction

Total BW for nrtPS = 2/3 remaining bandwidth. Individual Station：

Min(Max_BW_For_nrtPS , nrtPS_Loading). Total BW for BE = remaining – nrtPS Individual Station:

Min(Max_BW_For_BE , BE_Loading).

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Outline

Background WiMAX Standard Introduction Proposed Algorithm

Proposed Architecture. Bandwidth Allocation Description Packet Scheduling Description

Performance evaluation

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Packet Scheduling

Restrict by the DL/UL Map Gets bandwidth of each Service Classes, and

pick packets in the HOL of the corresponding queue and sends at appropriated PS

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Outline

Background WiMAX Standard Introduction Proposed Algorithm Performance evaluation-via simulation Conclusion

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Environment Setting

Packets: Poison Arrival Connection: Poison Arrival Compare my algorithm to [3] which is

following the rules of spec. BW: 10Mbps BS: 1 , SS: 5 Queue: no limit length

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Drop Rate (UGS, rtPS)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.5 0.6 1 1.3 1.5 1.7 1.9 2.2

Normalized Offered Load

Dro

p R

ate(

%)

Spec_UGS Spec_rtPS

Proporsed_UGS Proporsed_rtPS

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Drop Rate (only UGS)

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0.01

0.5 0.6 1 1.3 1.5 1.7 1.9 2.2

Normalized Offered Load

Dro

p R

ate(

%)

Spec_UGS

Proporsed_UGS

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Delay of real-time service

0

20

40

60

80

100

0.5 0.7 1 1.3 1.5 1.7 1.9 2.2

Normalized Offered Load

Tim

e(m

s)

Proporsed_UGS Proporsed_rtPSSpec_UGS Spec_rtPS

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Delay of non-real-time service

0

500010000

1500020000

2500030000

35000

0.5 0.7 1 1.3 1.5 1.7 1.9 2.2

Normalized Offered Load

Tim

e(m

s)

Proporsed_nrtPSProporsed_BESpec_nrtPSSpec_BE

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Bandwidth util. of Proposed BWA

0

0.2

0.4

0.6

0.8

1

0.5 0.6 1 1.3 1.5 1.8 1.9 2.2

Normalized Offered Load(%)

Thro

ughp

ut(%

)

Proporsed_UGS Proporsed_rtPS Proporsed_nrtPS

Proporsed_BE Total

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Compare of Bandwidth Util.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.5 0.7 1 1.3 1.5 1.7 1.9 2.2

Normalized Offered Load

Thro

ughp

ut(%

)

Proporsed_UGS Proporsed_rtPSSpec_UGS Spec_rtPS

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Fairness of real-time service

0.88

0.9

0.92

0.94

0.96

0.98

1

1.02

1 2 3 4 5 6 7 8 9 10Subscribe Station ID

Thro

ughp

ut(%

)

UGS UGS Average rtPS rtPS Average 0.975

0.98

0.985

0.99

0.995

1

1.005

1 2 3 4 5 6 7 8 9 10

Subscribe Station ID

Thro

ughp

ut(%

)

UGS UGS_AveragertPS rtPS_Average

0.8

0.85

0.9

0.95

1

1.05

1 2 3 4 5 6 7 8 9 10

Subscribe Station ID

Thr

ough

put(%

)

UGS Average_UGS rtPS Average_rtPS

Normalized Offered load(50%) Normalized Offered load(100%)

Normalized Offered load(150%)

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Outline

Background WiMAX Standard Introduction Proposed Algorithm Simulation Conclusion

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Conclustion

Provide Delay and Drop_Rate guarantee for UGS and rtPS

nrtPS has more bandwidth than BE Even in overloading , nrtPS and BE can get

some bandwidth.

40

Outline

Background WiMAX Standard Introduction Proposed Algorithm Simulation Conclusion Reference

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reference IEEE 802.16-2004

GuoSong Chu, Deng Wang, and Shunliang Mei, “A QoS Architecture for the MAC Protocol of IEEE 802.16 BWA System,” IEEE 2002 International Conference on Vol. 1,  29 June-1 July 2002 pp. 435-439, 2002.

Dong-Hoon Cho , Jung-Hoon Song, Min-Su Kim, and Kim-Jun Han, “Performance Analysis of the IEEE 802.16 Wireless Metropolitan Area Network,” First International Conference on Distributed Frameworks for Multimedia Applications (DFMA’05), pp. 130-137, 2005.

Kitti Wonghavarawat and Aura Ganz, “Packet Scheduling for QoS support in IEEE 802.16 broadband wireless access system,” International Journal of Communication Systems Vol. 16, Issue 1, pp.81-96.

Kin K. Leung and Arty Srivastava, “Dynamic Allocation of Downlink and Uplink Resource for Broadband Services in Fixed Wireless Networks,” IEEE Journal on Selected Areas in Communications Vol. 17 No. 5, May 1999.

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Q&A

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Virtual Map

123456

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SS1UGS

SS2UGS

SS3UGS

SS4UGS

SS1rtPS

SS2rtPS

SS3rtPS