FEC Performance in Large File Transfer over Bursty Channels

Frequent packet loss and large transmission delay cause the degradation in the quality of service (QoS) for real-time applications over the Internet, such as video streaming and voice over IP. In par-ticular, it is well known that a packet loss process with bursty nature significantly deteriorates the QoS of real-time applications in more extent than that with randomness. In this paper, we consider the impact of the burst loss process on the QoS of real-time applications over the Internet. Focusing on forward error correction (FEC) for QoS guarantee mechanism, we analyze its performance. For a burst-loss model, we consider a Gilbert model which is a two-state discrete-time Markov chain with good and bad states. We derive the block loss probability that original data eventually fails in transmission, and develop its efficient computational algorithm. For numerical examples, we consider the transmission of uncompressed high definition television (HDTV) as a real-time appli-cation, and show how the packet loss process affects the frame-level QoS of uncompressed HDTV. Numerical results show that the block loss probability increases as the packet loss process becomes bursty. They also demonstrate how the redundancy of FEC is effective in recovering lost packets for the frame-level QoS guarantee of uncompressed HDTV