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A Flexible Bandwidth Management Scheme in Bluetooth. Chin-Fu Liu Multimedia and Communications Laboratory Department of Computer Science and Information Engineering National Chi Nan University Taiwan, R.O.C. Advisor : Chun-Chuan Yang. Outline. Introduction
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A Flexible Bandwidth Management Scheme in Bluetooth Chin-Fu Liu Multimedia and Communications Laboratory Department of Computer Science and Information Engineering National Chi Nan University Taiwan, R.O.C. Advisor : Chun-Chuan Yang
Outline • Introduction • Basic Version of Bandwidth-Based Polling (BBP-bas) Scheme • Extended Version (BBP-ext) • Scheduling algorithm for BBP-ext • Performance Evaluation • Conclusion
Introduction - Bluetooth • Low cost • Low complexity • In a small area • Piconet
Introduction • Time Division Duplex • Master based polling
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
BBP notation • QoS-slave • SCO-slave • BE-slave (best effort slaves) • BBP-bas • BBP-ext
Bandwidth Based Polling Scheme - Basic versionBasic idea and slots allocation for QoS slaves • Framing structure of time slots • Dynamic frame for flexibility • Polling many times
Bandwidth Based Polling Scheme - Basic versionBasic idea and slots allocation for QoS slaves • DH11 = DH5+DH5+DH1 • DH5 > DH3 >> DH1 • Maximum polling times
PicoFrameSize & PicoFrameLimit Master Slavei (BwRqi) RequestSlot & Framelimit Bandwidth Based Polling Scheme - Basic versionBasic idea and slots allocation for QoS slaves • Progressive bandwidth allocation • Negotiation process
Bandwidth Based Polling Scheme - Basic versionQoS slave actions • #Bytesi = BwRQi * PicoFrameLimit * 625μs • Payload type :ByteCount >= #Bytesi or DH5*K
Bandwidth Based Polling Scheme - Basic versionQoS slave actions FrameLimiti=(RequestSloti Byte#)/(BwRQi*625μs)
Bandwidth Based Polling Scheme - Basic versionMaster actions • PicoFrameSize - by RequestSloti • PicoFrameLimit - by FrameLimiti
Bandwidth Based Polling Scheme - Extended versionSupport SCO-Slave • SCO link - Isochronous service by TSCO • HV3 TSCO=6 (64Kbps CBR service) • Adaptive TSCOEx:TSCO =16 (24Kbps) • Soft SCO links - Jitters due to shifting
Bandwidth Based Polling Scheme - Extended versionSupport SCO-Slave
Bandwidth Based Polling Scheme - Extended versionSupport Best Effort Slave (BE-Slave) • Equilibrium state • Unused Slots = PicoFrameLimit - PicoFrameSize • Slots quantum = (PFL-PFS)/(# of BE-slaves)
Bandwidth Based Polling Scheme - Extended versionPacket format in BBP-Ext Original Packet Master→QoS slave QoS slave→Master Master→BE slave BE slave→Master
Scheduling algorithm for BBP-extScheduling all kinds of slaves • Round RobinS1=DH3 S2=DH8 S3=DH10 TSCO=10
Scheduling algorithm for BBP-extDelay/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
Performance EvaluationSimulation Env & Performance Criteria • 1 slot=625μs • Bandwidth utilization • Fairness and flexibility with QoS slaves • Maximum shift in SCO links
Performance EvaluationSimulation Result & Discussion K=4 Req=150K
Performance Evaluation – Case 1Simulation Result & Discussion K=1
Performance Evaluation – Case 1Simulation Result & Discussion K=4
Performance Evaluation - Case 2Simulation Result & Discussion K=4 TSCO=10
Performance Evaluation – Case 3Simulation Result & Discussion K=4 TSCO=10
Performance Evaluation – Case 4Simulation Result & Discussion
Performance EvaluationSimulation Result & Discussion K=1 K=2 K=4 K=8
Conclusion • A dynamic framing structure • Distributed Mechanism • Minimal Control signaling • Good performance and flexibility by BBP • Future WorkMaster’s request Admission controlBluetooth 2.0