An efficient retransmission strategy for multi-source multi-destination relay networks over Rayleigh flat fading channels.

This paper considers the reliable transmission for wireless multisource multidestination relay networks where multiple sources want to distribute information to a set of destinations with the assistance of a relay. Simply, applying automatic repeat request (ARQ) protocols for retransmission of lost or erroneous packets may cause a considerable delay with a significantly increased number of retransmissions when multiple sources and multiple destinations are taken into consideration. To solve this problem, we propose a new ARQ protocol based on network coding (NC) to significantly reduce the number of retransmissions of the lost packets. In our proposed NC-based ARQ protocol, the relay detects packets from different sources, then combines and forwards the packets which are lost at the destinations using NC. In order to guarantee that all lost packets are retransmitted in an efficient way, we propose two packet-combination algorithms for the retransmissions at the relay and sources. Furthermore, we analyze the transmission bandwidth of different ARQ protocols over Rayleigh flat fading channels and provide the numerical results to demonstrate the superior performance of the proposed NC-based ARQ protocol over some existing schemes.