Fountain-inspired erasure coding for real-time traffic
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An erasure correction strategy based on fountain coding is proposed for traffic with real-time requirements. A sliding window marks the range of non-expired data. Each new block entering the window is once sent as such, followed by probabilistically sending a repair packet. The repair packets are formed as a random combination of the blocks in the current window using a degree distribution as in LT coding. The performance of the method with a given channel loss probability is analyzed using a Markov chain model. The state space, however, has to be truncated for computational tractability. The truncation error is verified to be small enough by simulations. By using the analytical model the optimal degree distribution is found to be of single-degree type. The performance of the proposed scheme is compared with deterministic settings, in which repair packets are sent after fixed number of systematic packets. Further comparison is made against Raptor coding, and we note that using the presented strategy can result in better performance in some situations.
KeywordsFountain coding Erasure coding Markov chain Real-time traffic Simulation
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- 1.3GPP TS 26.346 v.8.1.0 (2008). Technical specification group services and system aspects; multimedia broadcast/multicast service; protocols and codecs (Tech. rep.). 3GPP. Available online at http://www.3gpp.org.
- 2.Bogino, M. C., Cataldi, P., Grangetto, M., Magli, E., & Olmo, G. (2007). Sliding-window digital fountain codes for streaming of multimedia contents. In IEEE international symposium on circuits and systems. Google Scholar
- 4.Elliott, E. (1963). Estimates of error rates for codes on burst-error channels. Bell Systems Technical Journal, 42, 1977–1997. Google Scholar
- 5.Gilbert, E. (1960). Capacity of a burst-error channel. Bell Systems Technical Journal, 39, 1253–1266. Google Scholar
- 6.Luby, M. (2002). LT codes. In The 43rd annual IEEE symposium on foundations of computer science (pp. 271–282). Google Scholar
- 7.Luby, M., Shokrollahi, A., Watson, M., & Stockhammer, T. (2007). RFC 5053: raptor forward error correction scheme: scheme for object delivery (Tech. rep.). IETF. Google Scholar
- 8.Luby, M., Watson, M., Gasiba, T., Stockhammer, T., & Xen, W. (2006). Raptor codes for reliable download delivery in wireless broadcast systems. In Proceedings of IEEE consumer communications and networking conference, CCNC 2006 (pp. 192–197). Google Scholar
- 11.Tirronen, T., & Virtamo, J. (2008). Finding fountain codes for real-time data by fixed point method. In Proceedings of international symposium on information theory and its applications, ISITA 2008. Google Scholar