Emerging IPTV technology uses source-specific IP multicast to deliver TV programs to the end-users. To provide timely and reliable services over the error-prone DSL access networks, a combination of multicast forward error correction and unicast retransmissions is employed to mitigate the impact of impulse noise. In current systems, the retransmission function is provided by the Retransmission Servers. We propose an alternative distributed solution where the burden of loss repair is partially shifted to the peer IP settop boxes. Through the Peer-assisted Repair (PAR) protocol, we demonstrate how the packet repairs can be delivered in a timely, reliable and decentralized manner using the combination of server-peer coordination and coded redundant repairs. We show through analysis and simulations that this new solution not only effectively mitigates the bottleneck experienced by the Retransmission Servers, thus greatly improving the scalability of the system, but also efficiently dea...
Zhi Li, Xiaoqing Zhu, Ali C. Begen, Bernd Girod