Encoded packet-assisted reliable transmission for unicast sessions in wireless networks

In this paper, we propose an encoded packet-assisted retransmission, namely EAR, approach that use opportunistic network coding (ONC) to improve the bandwidth efficiency for unicast sections in wireless networks. In existing ONC schemes, network coding opportunity are not always fully exploited due to the lack of understanding of the use of the encoded packets receivers cannot decode. To overcome this limitation, EAR develops an improved opportunistic listening mechanism that allows receivers to store all heard undecodable ONC packets and to periodically report the reception status to the sender. The sender then can directly XOR these encoded packets with other packets to exploit the potential coding opportunities of them. To further maximize the utilization of coding opportunity in the network, EAR introduces a greedy coding algorithm that constructs a simple scheduler. The scheduler prioritizes packets according to their contribution to the overall transmission performance. Simulation results show that, EAR can significantly reduce the total number of retransmissions and provide more efficient bandwidth utilization, compared with existing schemes.