Topology-Aware Network Coding for Wireless Multicast

In this paper, we present a topology-aware network coding (TANC) technique for wireless multicast systems aiming at reducing packet retransmissions in a lossy propagation environment. In addition to radio channel impacts, packet loss may result from traffic congestion, thereby yielding different retransmission requests. In such a wireless network coding multicast environment, what is the best packet combination to minimize the packet retransmissions for a number of users? We make progress on this problem by taking advantage of the network topology information to select the appropriate lost encoded packets in the encoding phase. We leverage the capability of software-defined networking controller to construct the global network topology in the proposed TANC scheme. Experimental results show that the proposed TANC scheme can reduce 52.4% of packet retransmissions compared to the existing random linear network coding in different environments, including various numbers of uncoded packets, network nodes, and packet loss probabilities.