In interactive voice applications, FEC allows to recover from losses. FEC schemes need to be simple in order to allow interactivity. We study a simple scheme implemented in FreePhone audio tool [High Speed Networking Group, INRIA, Sophia Antipolis, http://www-sop.inria.fr/rodeo/fphone] and RAT: Robust Audio Tool [Multimedia Integrated Conferencing for European Researchers, University College, London], where for every packet n, redundant information is added in packet n+. The quality of a reconstructed copy depends on the amount of redundancy. Using queuing analysis we obtain simple expressions for the audio quality as a function of the amount of redundancy. We show that the expected amount of useful information deteriorates for any amount of FEC and any . We find conditions under which FEC leads to quality improvement.
Queuing analysis of simple FEC schemes for voice over IP
Computer Networks, Volume 39, Issue 2-5, June 2002
© Elsevier. Personal use of this material is permitted. The definitive version of this paper was published in Computer Networks, Volume 39, Issue 2-5, June 2002 and is available at : http://dx.doi.org/10.1016/S1389-1286(01)00309-7
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