Efficient retransmission with network coding for multiple flows in wireless networks

Recently, network coding technique has emerged as a promising data transport paradigm for communication networks. In wireless networks, when network coding is applied to data recovery, an intermediate node is able to simultaneously delivery multiple loss packets destined to different destinations with a single retransmission. However, in existing retransmission scheme with opportunistic network coding for multiple unicast flows, only native packets are used in coding process. In addition, destination nodes usually erase the encoded packets they cannot decode. In this paper, we propose an efficient retransmission approach that employs opportunistic network coding for multiple unicast flows. Our approach enables nodes to exploit the potential benefits of encoded packets to create more coding opportunities. Moreover, we present a redistribution algorithm to further reduce the number of retransmissions. Simulation results for wheel networks indicate that significant performance improvement in term of the average number of retransmissions, compared with existing schemes that can be achieved.