A new hybrid ARQ protocol for two-way relay networks

In order to improve the throughput, robustness and resource utilization of relay network, we develop a new high-efficiency and stable two-way relay system with double antenna relay node, which employs combining Maximum Likelihood(ML) detection and Network Coding during access and broadcast stage respectively. It is not sensitive to link asymmetry compare with physical network coding(PNC), and can improve throughput by 50% compare with traditional three time slot relay network. This paper also employs and develops a novel automatic repeat request(ARQ) strategy to retransmit the corrupt packet, by using combination at the receiver, the users can recover the corrupt packet with negligible retransmission overhead. Numerical analysis and simulation results demonstrate that our proposed system can get a remarkable throughput improvement.