1 Audio Streaming over Audio Streaming over Bluetooth Scatternet: Bluetooth Scatternet: using Adaptive Link using Adaptive Link Layer Layer Team members: Sewook Jung, Jungsoo Lim, Soon Team members: Sewook Jung, Jungsoo Lim, Soon Young Oh Young Oh Tutor: Ling-Jyh Chen Tutor: Ling-Jyh Chen Professor Mario Gerla Professor Mario Gerla CS218 – Fall 2003 CS218 – Fall 2003
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1 Audio Streaming over Bluetooth Scatternet: using Adaptive Link Layer Team members: Sewook Jung, Jungsoo Lim, Soon Young Oh Tutor: Ling-Jyh Chen Professor.
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Audio Streaming over Audio Streaming over Bluetooth Scatternet: Bluetooth Scatternet: using Adaptive Link using Adaptive Link LayerLayer
Team members: Sewook Jung, Jungsoo Lim, Soon Young Team members: Sewook Jung, Jungsoo Lim, Soon Young OhOh
Previous ResearchPrevious Research Related workRelated work ImplementationsImplementations SimulationsSimulations ConclusionConclusion Future WorkFuture Work
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BackgroundBackground
Multimedia contents are prosperous Multimedia contents are prosperous – Eg. MP3 audio Eg. MP3 audio
Wireless Personal Area Network (PAN) needs Wireless Personal Area Network (PAN) needs to support multimediato support multimedia
The varying nature of the wireless link can The varying nature of the wireless link can make streaming over wireless a challenging make streaming over wireless a challenging problemproblem
Packets are arrived to client with a consistent Packets are arrived to client with a consistent raterate
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Background (cont’d)Background (cont’d)
ARQ mechanismARQ mechanism– Packets being dropped/delayed in bad linkPackets being dropped/delayed in bad link– Beneficial to non-real-time trafficBeneficial to non-real-time traffic– Need modifications for real-time/streaming trafficNeed modifications for real-time/streaming traffic
ARQ retransmission limitARQ retransmission limit– Too highToo high
Packets are severely delayedPackets are severely delayed Streaming audio/video quality is degradedStreaming audio/video quality is degraded
– Too lowToo low large number of packets are dropped at the link layerlarge number of packets are dropped at the link layer Also causes poor audio quality.Also causes poor audio quality.
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An Adaptive ARQ RTOAn Adaptive ARQ RTO
Original BluetoothOriginal Bluetooth– stop-and-wait ARQstop-and-wait ARQ scheme at link layer scheme at link layer
packet is retransmitted until receives ACK packet is retransmitted until receives ACK or retransmission timeout (RTO) is or retransmission timeout (RTO) is exceeded.exceeded.
– In most current Bluetooth chipsetsIn most current Bluetooth chipsets the default RTO is infinitethe default RTO is infinite To provide reliable link.To provide reliable link.
Fixed ARQ RTOFixed ARQ RTO– Use a fixed finite RTOUse a fixed finite RTO– Impossible to accommodate all different link Impossible to accommodate all different link
qualities with one fixed value.qualities with one fixed value. Adaptive ARQ RTOAdaptive ARQ RTO
– Adjust RTO by measurement of previous RTTAdjust RTO by measurement of previous RTT– Improvement on average delay time and the Improvement on average delay time and the
Previous Research Previous Research (cont’d)(cont’d) Set the upper bound and lower Set the upper bound and lower
bound for ARQ RTObound for ARQ RTO RTORTOmin min = 2 X T= 2 X Tpackets packets (= 6*625ms in (= 6*625ms in
DH5)DH5) RTORTOmax max = T= Tpackets packets X Max(Available Buffer X Max(Available Buffer
X 75%, 2)X 75%, 2)TTpacketpacket = time interval between first packet = time interval between first packet fragments and last fragments’ ACKfragments and last fragments’ ACKAvailable buffer = (system maximum input Available buffer = (system maximum input buffer – buffer – used buffer)/packet size used buffer)/packet size
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Previous Research Previous Research (cont’d)(cont’d) Adaptive ARQ RTO ResultsAdaptive ARQ RTO Results
– Enhance the streaming audio quality Enhance the streaming audio quality remarkablyremarkably
– Robust solution for Robust solution for real-time/streaming data over real-time/streaming data over wireless network.wireless network.
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Related workRelated work
TCP-Friendly Rate Control (TFRC): TCP-Friendly Rate Control (TFRC): equation based TCP rate controlequation based TCP rate control
Video Transport Protocol (VTP): sender Video Transport Protocol (VTP): sender adjust the sending rate based on adjust the sending rate based on estimated eligible rateestimated eligible rate
RAP: End-to-end Rate Based Control: RAP: End-to-end Rate Based Control: mimics TCP’s AIMD behaviormimics TCP’s AIMD behavior
RCS: A Rate Control Scheme: source RCS: A Rate Control Scheme: source probes the connection with dummy probes the connection with dummy packets, and adjust sending ratepackets, and adjust sending rate
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ImplementationsImplementations
Blueware: Blueware: – Developed by MITDeveloped by MIT– Bluetooth simulator as an extension Bluetooth simulator as an extension
to NSto NS– Various Scatternet formation and Various Scatternet formation and
link scheduling schemes.link scheduling schemes.
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Implementations Implementations (cont’d) (cont’d)
Applications
L2CAP
Bluetooth Radio
Host Controller Interface
Bluetooth Baseband
LMP
Bluetooth Stack
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Implementations Implementations (cont’d) (cont’d)
Topology formationTopology formation Manipulate the topology formationManipulate the topology formation
– Set position of nodes manuallySet position of nodes manually– Original Blueware has only random topology formationOriginal Blueware has only random topology formation
The examples of topology formations:The examples of topology formations:
– Blueware supports packet error rate Blueware supports packet error rate (PER) instead of bit error rate (BER)(PER) instead of bit error rate (BER)
– DH5 mode is used for all RTP packets DH5 mode is used for all RTP packets where packet size is 2712 bits and a where packet size is 2712 bits and a packet length is five Bluetooth slotspacket length is five Bluetooth slots
– PERPER is defined as is defined asP = 1 – (1 – b)P = 1 – (1 – b)ss
b = bit error rate, s = packet size b = bit error rate, s = packet size
– once the error starts, the probability of once the error starts, the probability of having an error in the next bit is having an error in the next bit is extraordinarily high such as 90%. extraordinarily high such as 90%.
– If the burst error occurs in the middle of If the burst error occurs in the middle of the packet, it may not affect the next the packet, it may not affect the next packet.packet.
– However, if it occurs at the end of the However, if it occurs at the end of the packet, there is a great probability of packet, there is a great probability of affecting the next packet. affecting the next packet.
Combination of Adaptive Packet Type Combination of Adaptive Packet Type (APT) and Adaptive RTO(APT) and Adaptive RTO– Combine adaptive RTO scheme with adaptive Combine adaptive RTO scheme with adaptive
packet type (i.e. DH5, DH3, DH1, DM5, DM3, packet type (i.e. DH5, DH3, DH1, DM5, DM3, DM1)DM1)
– Choose the best packet type for different BER Choose the best packet type for different BER rangesranges
– Implement the functionality to the Bluetooth Implement the functionality to the Bluetooth LC layerLC layer
– Optimal packet type can be selected Optimal packet type can be selected dynamicallydynamically
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ReferencesReferences
J.C. Haartsen, " J.C. Haartsen, " The The BluetoothBluetooth Radio System Radio System," IEEE Personal ," IEEE Personal Communications Magazine, Feb. 2000.Communications Magazine, Feb. 2000.
NS2 Simulator: NS2 Simulator: http://www.http://www.isiisi..eduedu//nsnamnsnam/ns//ns/ L.-J. Chen, R. Kapoor, K. Lee, M. Y. Sanadidi, M. Gerla, " L.-J. Chen, R. Kapoor, K. Lee, M. Y. Sanadidi, M. Gerla, "
Audio Streaming over Audio Streaming over BluetoothBluetooth: An Adaptive ARQ Timeout Approach: An Adaptive ARQ Timeout Approach,","
Reza Rejaie, Mark Handley, Deborah Estrin, "Reza Rejaie, Mark Handley, Deborah Estrin, " RAP: An End-to-end Rate-based Congestion Control Mechanism for RAP: An End-to-end Rate-based Congestion Control Mechanism for RealtimeRealtime Streams in the Internet Streams in the Internet," In Proceedings of IEEE INFOCOM ," In Proceedings of IEEE INFOCOM 1999. 1999.
G. Holland, and N. Vaidya,"G. Holland, and N. Vaidya," Analysis of TCP performance over mobile ad hoc networks Analysis of TCP performance over mobile ad hoc networks ," In ," In Proceedings of ACM Mobicom'99, Seattle, Washington, 1999. Proceedings of ACM Mobicom'99, Seattle, Washington, 1999.
Balk, D. Maggiorini, M. Gerla, and M. Y. Sanadidi, " Balk, D. Maggiorini, M. Gerla, and M. Y. Sanadidi, " Adaptive MPEG-4 Video Streaming with Bandwidth EstimationAdaptive MPEG-4 Video Streaming with Bandwidth Estimation, ", , ", UCLA. UCLA.
J. Tang, G. Morabito, I. F. Akyildiz, and M. Johnson, "J. Tang, G. Morabito, I. F. Akyildiz, and M. Johnson, "RCS: A Rate Control Scheme for Real-Time Traffic in Networks with HRCS: A Rate Control Scheme for Real-Time Traffic in Networks with High Bandwidth-Delay Products and High Bit Error Ratesigh Bandwidth-Delay Products and High Bit Error Rates," In Proceedings of Infocom 2001, Anchorage, AK, 2001. ," In Proceedings of Infocom 2001, Anchorage, AK, 2001.