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A Flexible Bandwidth Management Scheme

in Bluetooth

Chin-Fu LiuMultimedia and Communications LaboratoryDepartment of Computer Science and Information EngineeringNational Chi Nan UniversityTaiwan, R.O.C.

Advisor : Chun-Chuan Yang

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Outline

Introduction Basic Version of Bandwidth-Based Polling

(BBP-bas) Scheme Extended Version (BBP-ext) Scheduling algorithm for BBP-ext Performance Evaluation Conclusion

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Introduction - Bluetooth

Low cost Low complexity In a small area Piconet

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Introduction

Time Division Duplex

Master based polling

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Introduction

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Introduction – QoS Support in BT.

Goals of bandwidth management1.Bandwidth satisfaction2.Fairness

Goal of Bandwidth-Based Polling (BBP) 1.Bandwidth management2.Minimal Control signaling3.Lower Jitter on SCO links

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BBP notation

QoS-slave SCO-slave BE-slave (best effort slaves)

BBP-bas

BBP-ext

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Bandwidth Based Polling Scheme - Basic version

Basic idea and slots allocation for QoS slaves

Framing structure of time slots Dynamic frame for flexibility Polling many times

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Bandwidth Based Polling Scheme - Basic version

Basic idea and slots allocation for QoS slaves

DH11 = DH5+DH5+DH1 DH5 > DH3 >> DH1 Maximum polling times

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Bandwidth Based Polling Scheme - Basic version

Basic idea and slots allocation for QoS slaves

Progressive bandwidth allocation

Negotiation process

MasterSlavei

(BwRqi)

PicoFrameSize & PicoFrameLimit

RequestSlot & Framelimit

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Bandwidth Based Polling Scheme - Basic version

QoS slave actions

#Bytesi = BwRQi * PicoFrameLimit * 625μs Payload type :

ByteCount >= #Bytesi or DH5*K

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Bandwidth Based Polling Scheme - Basic version

QoS slave actions

FrameLimiti=(RequestSloti Byte#)/(BwRQi*625μs)

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Bandwidth Based Polling Scheme - Basic version

Master actions

PicoFrameSize - by RequestSloti

PicoFrameLimit - by FrameLimiti

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Bandwidth Based Polling Scheme - Extended version

Support SCO-Slave

SCO link - Isochronous service by TSCO

HV3 TSCO=6 (64Kbps CBR service)

Adaptive TSCO

Ex:TSCO =16 (24Kbps) Soft SCO links - Jitters due to shifting

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Bandwidth Based Polling Scheme - Extended version

Support SCO-Slave

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Bandwidth Based Polling Scheme - Extended version

Support Best Effort Slave (BE-Slave)

Equilibrium state Unused Slots = PicoFrameLimit - PicoFrameSize Slots quantum = (PFL-PFS)/(# of BE-slaves)

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Bandwidth Based Polling Scheme - Extended version

Packet format in BBP-Ext

Original Packet

Master→QoS slave

QoS slave→Master

Master→BE slave

BE slave→Master

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Scheduling algorithm for BBP-ext

Scheduling all kinds of slaves

Round RobinS1=DH3 S2=DH8 S3=DH10 TSCO=10

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Scheduling algorithm for BBP-ext

Delay/Jitter analysis

Reasons for shifting:(1) Undividable packet

of QoS-slave (2) Other SCO-slaves

Maximum shift → 4+(N-1)*2 Slots Tsniff=TSCO

Nsniff-attempt=Maximum shift

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Performance Evaluation

Simulation Env & Performance Criteria

1 slot=625μs Bandwidth utilization Fairness and flexibility with QoS slaves Maximum shift in SCO links

(Kbps) Slave 1 Slave 2 Slave 3 Slave 4 Slave 5 Slave 6 Slave 7 Remarks

Test case 1 50 75 100 125 150 175 N/A 6 QoS

Test case 2 50 75 100 125 150 Tsco=10 N/A 5 QoS, 1 SCO

Test case 3 50 100 150 200 Tsco=10 BE N/A 4 QoS, 1 SCO, 1 BE

Test case 4 50(0 ~ 2s)

75(0 ~ 2s)

200(0 ~ 2s)

150(0 ~ 2s)

100(0 ~ 2s)

150(0 ~ 1s)

N/A Slave 6 leaves early

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Performance Evaluation

Simulation Result & DiscussionK=4 Req=150K

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Performance Evaluation – Case 1

Simulation Result & DiscussionK=1

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Performance Evaluation – Case 1

Simulation Result & DiscussionK=4

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Performance Evaluation - Case 2

Simulation Result & DiscussionK=4 TSCO=10

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Performance Evaluation – Case 3

Simulation Result & DiscussionK=4 TSCO=10

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Performance Evaluation – Case 4

Simulation Result & Discussion

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Performance Evaluation

Simulation Result & Discussion

K=1 K=2

K=4 K=8

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Conclusion

A dynamic framing structure Distributed Mechanism Minimal Control signaling Good performance and flexibility by BBP Future Work

Master’s request Admission controlBluetooth 2.0