An Efficient Reliable Multicast Framework Based on Network Coding in Multi-hop Wireless Networks

Providing reliable multicast service in multi-hop wireless network faces many technique challenges, among which packet loss recovery is one of most important issues. In this paper, an efficient packet loss recovery framework is proposed based on random linear network coding in field for reliable multicast in multi-hop wireless networks, called Network Coding Reliable Multicast (NCRM). NCRM overcomes the limitations of the XOR encoding scheme. The original packets are classified into different generations and sent. Repair nodes employ random linear network coding to send encoded packets. A group member who experiences packet loss sends a Negative ACKnowledgement (NACK) with loss bit vector. Through neighborhood recovery, multi-hop recovery and/or source recovery, loss recovery is efficiently fulfilled. A mathematical model of homogeneous Markov chain is constucted to analyze the theoretical delay and average hops of retransmission. Simulation experiments based on NS2 and the numerical results demonstrate that NCRM significantly outperforms Pragmatic General Multicast (PGM) and CoreRM, in terms of network throughput and loss recovery latency.