Network-embedded FEC for optimum throughput of multicast packet video

Forward error correction (FEC) schemes have been proposed and used successfully for multicasting realtime video content to groups of users. Under traditional IP multicast, application-level FEC can only be implemented on an end-toend basis between the sender and the clients. Emerging overlay and peer-to-peer (p2p) networks open the door for new paradigms of network FEC. The deployment of FEC within these emerging networks has received very little attention (if any). In this paper, we analyze and optimize the impact of network-embedded FEC (NEF) in overlay and p2p multimedia multicast networks. Under NEF, we place FEC codecs in selected intermediate nodes of a multicast tree. The NEF codecs detect and recover lost packets within FEC blocks at earlier stages before these blocks arrive at deeper intermediate nodes or at the final leaf nodes. This approach significantly reduces the probability of receiving undecodable FEC blocks. In essence, the proposed NEF codecs work as signal regenerators in a communication system and can reconstruct most of the lost data packets without requiring retransmission. We develop an optimization algorithm for the placement of NEF codecs within random multicast trees. Based on extensive H.264 video simulations, we show that this approach provides significant improvements in video quality, both visually and in terms of PSNR values. r 2005 Elsevier B.V. All rights reserved. Keyword: FEC; Network coding; Multicast; Peer–peer; Video e front matter r 2005 Elsevier B.V. All rights reserve age.2005.05.002 work has been presented as: Mingquan Wu, e, and Hayder Radha, ‘‘Network-Embedded for Optimum Throughput of Multicast Packet tional Packet Video Workshop (PV), December adha and MingquanWu, ‘‘Overlay and Peer-toia Multicast with Network-Embedded FEC’’, onal Conference on Image Processing (ICIP), ng author. Tel.: +1734 7633178. sses: [email protected] (M. Wu), su.edu (S.S. Karande), [email protected]