Network coding-based block ACK for wireless relay networks

This paper considers block acknowledgement (BACK) mechanisms in wireless regenerative relay networks. Conventionally, a total of (2N+1) BACK packets are required in wireless regenerative N-relay networks to acknowledge the data transmission between the source and destination via the relays. In this paper, based on network coding (NC) we propose an efficient BACK scheme to significantly reduce the required acknowledgement load by N BACK packets. Importantly, by deriving the error probability of the determination of the packets to be retransmitted at the source or relays, it is found that the utilised NC helps improve the reliability of BACK transmissions. Furthermore, some asymptotic scenarios of the forward links are considered and a general expression of error probability in multi-relay networks is derived for each scenario. Finally, simulation results are shown to verify the analytical findings.