Multiple Trees with Network Coding for Efficient and Reliable Multicast in MANETs

The innovative exploitation of network coding technology could bring great design advantages to MANETs. First, wireless links are inherently lossy due to channel fading or interference. Second, the delivery condition of the route from the source to each receiver in a multicast transmission might be significantly distinct. Trying to satisfy the reliability requirement for the poorly-connected receivers may affect the performance of the rest of the receivers. In this paper, we present a tree-based multicast protocol, which exploits the characteristics of network coding to provide efficient and reliable multicast. A metric, named Receiving Probability (RP), is proposed to represent the probability for a node in a multicast tree to successfully receive a packet sent by the multicast source. To mitigate the distinctions among the receivers, the proposed multicast protocol aims to construct multiple trees such that the RP of each receiver satisfies a predefined threshold. Besides, since seldom redundant packets are generated with random network coding, by applying random network coding to these constructed multiple trees, differently coded packets can be transmitted on multiple trees, and the throughput of the reliable multicast can be improved. Simulation results show that the average throughput can be enhanced 30% and the throughput of the poorly-connected receivers can be enhanced 100% with our protocol, compared to a recent work.