UDP Lite for Real-Time Wireless Video Almudena Konrad, Amoolya Singh, and Anthony Joseph University of California, Be...
Idea <ul><li>Problem </li></ul><ul><li>Current Internet doesn’t support bit error resilient codecs </li></ul><ul><li>Check...
Testbed, Protocols, Tools UDP / UDP Lite Socket Interface H.263+ Encoder transparent / non transparent transparent / non t...
<ul><li>Flexible checksumming scheme allows corrupted data to be transmitted to the application </li></ul><ul><li>“ length...
<ul><li>Transparent Mode </li></ul><ul><li>no error control mechanism </li></ul><ul><li>Non-Transparent Mode </li></ul><ul...
Channel Simulator: WSim WSim Wireless Error Trace Input Video Stream Output Video Stream <ul><li>Allows “easy” performanc...
<ul><li>Experiment </li></ul><ul><li>Collect 4480 min of wireless video traces, (~4 min per video) </li></ul><ul><ul><li>B...
Experimental Results
End to End Delay
Inter-Arrival Time
Packet Loss
Video Screenshots UDP UDP Lite Experiment Simulation UDP UDP Lite
Discussion & Conclusions <ul><li>Reliability at link layer causes delay </li></ul><ul><li>Strict checksumming of UDP cause...
<ul><li>Provide real-time feedback on channel conditions </li></ul><ul><li>Provide rate control </li></ul><ul><li>Incorpor...
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Pres_Video_wireless2.ppt

Published on: Mar 4, 2016
Published in: Technology      Business      
Source: www.slideshare.net


Transcripts - Pres_Video_wireless2.ppt

  • 1. UDP Lite for Real-Time Wireless Video Almudena Konrad, Amoolya Singh, and Anthony Joseph University of California, Berkeley & Reiner Ludwig Ericsson Research
  • 2. Idea <ul><li>Problem </li></ul><ul><li>Current Internet doesn’t support bit error resilient codecs </li></ul><ul><li>Checksumming drops corrupted packets </li></ul><ul><li>“ Error resilience” of the codecs is disabled by network </li></ul><ul><li>Goal </li></ul><ul><li>Support real-time streaming applications over noisy channels, such as wireless </li></ul><ul><li>Proposed Solution </li></ul><ul><li>Provide link/transport layer alternatives to support error resilient video codecs </li></ul>
  • 3. Testbed, Protocols, Tools UDP / UDP Lite Socket Interface H.263+ Encoder transparent / non transparent transparent / non transparent MultiTracer SocketDUMP RLPDUMP Plotting & Analysis (MATLAB) RTP IP PPP Packetization RTP UDP / UDP Lite IP PPP De-packetization H.263+ Decoder Socket Interface Fixed Host Unix BSDi 3.0 GSM Base Station GSM Network PSTN Mobile Host Unix BSDi 3.0 SocketDUMP
  • 4. <ul><li>Flexible checksumming scheme allows corrupted data to be transmitted to the application </li></ul><ul><li>“ length” field in UDP header replaced by “coverage” field </li></ul><ul><li>Specifies how many bytes of payload to checksum </li></ul><ul><li>Implemented in BSDi 3.0 kernel (Keith Slower) </li></ul>UDP Lite (Larzon, Degemark, and Pink) source port # dest port # length / coverage checksum 0 7 8 15
  • 5. <ul><li>Transparent Mode </li></ul><ul><li>no error control mechanism </li></ul><ul><li>Non-Transparent Mode </li></ul><ul><li>Uses RLP (Radio Link Protocol), a semi-reliable ARQ protocol </li></ul><ul><ul><li>Link resets after N=7 number of re-transmissions </li></ul></ul><ul><li>Fixed frame size of 30 bytes (6 bytes header) </li></ul><ul><ul><li>Reliability at the cost of additional end-to-end delay </li></ul></ul><ul><li>Window size of 62 frames </li></ul><ul><li>Error recovery mechanisms </li></ul><ul><ul><li>Select - Reject (initiated by receiver) </li></ul></ul><ul><ul><li>Checkpointing (initiated by sender) </li></ul></ul>Physical / Radio Link Layer (GSM 9.6 kb/s)
  • 6. Channel Simulator: WSim WSim Wireless Error Trace Input Video Stream Output Video Stream <ul><li>Allows “easy” performance study of UDP-Lite, and error resilience functionalities </li></ul><ul><li>Simulates two protocol configurations: </li></ul><ul><ul><li>UDP, non-transparent and UDP Lite, transparent </li></ul></ul><ul><li>Uses 215 min of GSM wireless error traces collected in a poor channel environment </li></ul>
  • 7. <ul><li>Experiment </li></ul><ul><li>Collect 4480 min of wireless video traces, (~4 min per video) </li></ul><ul><ul><li>Bad channel conditions (signal strength ~2-3) </li></ul></ul><ul><li>Three different network configurations </li></ul><ul><ul><li>UDP, non-transparent </li></ul></ul><ul><ul><li>UDP, transparent </li></ul></ul><ul><ul><li>UDP-Lite, transparent </li></ul></ul><ul><li>For each trace, we calculated metrics </li></ul><ul><ul><li>end-to-end, inter-arrival time ,loss rate and throughput </li></ul></ul><ul><li>For each metric, we calculated statistics </li></ul><ul><ul><li>mean & std dev </li></ul></ul><ul><li>Simulation </li></ul><ul><li>Run Wsim on “mom” video stream using a wireless error trace of 1.5% BLER </li></ul>Performance Analysis
  • 8. Experimental Results
  • 9. End to End Delay
  • 10. Inter-Arrival Time
  • 11. Packet Loss
  • 12. Video Screenshots UDP UDP Lite Experiment Simulation UDP UDP Lite
  • 13. Discussion & Conclusions <ul><li>Reliability at link layer causes delay </li></ul><ul><li>Strict checksumming of UDP causes poor “error resilience” at application </li></ul><ul><li>UDP Lite (with GSM in transparent mode) provides </li></ul><ul><ul><li>less end to end delay </li></ul></ul><ul><ul><li>constant jitter </li></ul></ul><ul><ul><li>higher throughput </li></ul></ul><ul><ul><li>lower packet loss </li></ul></ul><ul><ul><li>… than UDP (with GSM in non-transparent mode) </li></ul></ul><ul><li>In general, can choose protocol combination appropriate for application </li></ul>UDP Lite /transparent UDP / RLP tolerant & daptive * UDP / RLP TCP / RLP Protocol Choice Type of Application Adaptive real-time: vic, vat Hard real-time: wb, v-conf Interactive: telnet, web Batch: email, ftp Example intolerant & rigid *
  • 14. <ul><li>Provide real-time feedback on channel conditions </li></ul><ul><li>Provide rate control </li></ul><ul><li>Incorporate unequal error protection for MPEG4 </li></ul>Future Work

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