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Path Virtualization Using Fountain Code for Video Streaming over Heterogeneous Networks

Path Virtualization Using Fountain Code for Video Streaming over Heterogeneous Networks. Sang-Chun Han Hwangjun Song Jun Heo. 05/05 Feb 2009. International Conference on Intelligent Hiding and Multimedia Signal Processing (IIH-MSP), Feb, 2008. Outline. Introduction Proposed Algorithm

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Path Virtualization Using Fountain Code for Video Streaming over Heterogeneous Networks

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  1. Path Virtualization Using Fountain Code for Video Streaming over Heterogeneous Networks Sang-Chun Han Hwangjun Song Jun Heo 05/05 Feb 2009 International Conference on Intelligent Hiding and Multimedia Signal Processing (IIH-MSP), Feb, 2008.

  2. Outline • Introduction • Proposed Algorithm • Experimental Results • Conclusion

  3. IntroductionTo satisfy required QoSin wireless network (1/4): • Fast Vertical Handoff:

  4. Introduction To satisfy required QoS in wireless network (2/4): • When multiple wireless networks are available: • Fast Vertical Handoff: • Involves changing the data link layer (Layer 2) technology. • e.g. Between WLAN (802.11x) and UMTS (CDMA2000) • Different from Horizontal Handoff between different AP. • Between same technology only involved in Layer 3. • Drawbacks: • Sophisticated architecture, implementation cost, and a little transition time is unavoidable.

  5. IntroductionTo satisfy required QoSin wireless network (3/4): • Path Diversity (provide a Virtual Path): Virtual Path ※ ThisVirtual Path is consisted of 2physical paths.

  6. Introduction To satisfy required QoS in wireless network (4/4): • When multiple wireless networks are available: • Path Diversity: • The Mobile Node must provide more than one network interface. • Objective of proposed algorithm: • To provide a Virtual Pathfor video streaming by combining Path Diversity Technology, H.264 codec Rate Control, and Fountain Code.

  7. Proposed Algorithm ※ Feedback Info are sent: (i) periodically: pre-determined time is expired. (ii) when thecondition of virtual path changes significantly: m: The number of physical paths consisting of a Virtual Path.

  8. Proposed Algorithm Bgop: the amount of output bits for a GOP. PS: packet's payload size.

  9. Proposed Algorithm Problem Formulation: • Find the maximum encoding rate ( VRmax ) and code rate ( C ) for video streaming subject to , and , where d: Delay dmax: Tolerable Maximum Delay pblr: Block Loss Rate pmax: Tolerable Maximum Block Loss Rate

  10. Proposed Algorithm Problem Formulation: • Step 1. Initialization: • Derive Source Block Length: Bgop: the amount of output bits for a GOP. PS: packet's payload size.

  11. Proposed Algorithm Problem Formulation: ※ PS: packet's payload size. • Step 2. Find Maximum Transmission Rate (TRmax): • The delay to transmit a packet though the ith path by: • The number of packets that are transmitted though the ith pathsatisfying the delay constraint: • Therefore, the MaximumTransmission Rate of a virtual path: ngop: the number of frames in a GOP. fr: frame rate of video.

  12. ※ If: K=5, C=1/2 t = 10 Assume K’ = 6, Summation from i=5~10 means: Proposed Algorithm Problem Formulation: All decoding failurecases! • Step 3. Determine the Code Rate (C): • Now we can calculate BLR function P(K, C) as follows: , where and . • We have to find largest C which satisfies: • Consequently, the Maximum Encoding Rate (VRmax) is determined by:

  13. Experimental Results ※ Java is used to implement the proposed system.

  14. Experimental Results • The authors assume there are only two heterogeneous paths between a video server and a client. • 802.11b and 802.11g • Tolerable Maximum: • Delay: 500ms • Block Loss Rate: 0.01 • Reference Software of H.264/AVC: • JM12.4 • Original JM Rate Control Mechanism are used.

  15. Experimental Results • GOP: • Number of frames: 15 • Structure is “IPPP…” • Video sequence: • CIF format HARBOUR. • It consisted only 300 frames at 30fps. • Simply repeat the same video sequence to support the 25sec experiment time.

  16. Experimental Results ※ Code rate decreases when PLR increases: Decoding Prob. is kept in the tolerable rangeat the cost of increased redundancy.

  17. Code Rateand Video Encoding Rateare adaptive to the wireless channel status. Thus, the number of packets received through Virtual Path is always higher than K‘. Experimental Results ※ The number of packets in a source block is changed according to Delay. The number of GOP

  18. Experimental Results • The authors also experimented in the same condition with Reed-Solomon code. • (255, 223) RS code, for R = 1.14 • The same condition: • “Second path” is more reliable than “First path”. • Always successfully decoded using only “Second path”. • Sometimes not decodable using two paths: 8th and 40th GOP are not decodable. • Video freezes during 0.5 second when frame repetition method is used to conceal the loss.

  19. Experimental Results

  20. Conclusion • By the experiment in the real wireless environment, the authors showed that Virtual Path using Fountain Code consolidates multiple paths for video streaming. • This approach support higher bandwidth, lower delay, and lower BLR than traditional approach which use only one network at a time. • In addition, seamless video streaming serviceis possible without a Vertical Handoff Time.

  21. Thank you!

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