A relay-based retransmission scheme via analog network coding in wireless cooperative communication systems

Network coding has recently been applied to wire-less networks for its ability to improve network throughput. Early research works in wireless network coding mainly focused on bit level operation in Galois field which has been proved well suited to wireline networks where the channel is almost invariable. Nevertheless, traditional network coding does not work well in the scenario of wireless networks due to the time variable property of the wireless channel. Instead, the proposals of the physical layer network coding and the analogue network coding attempt to the signal level coding operation. In this paper, analogue network coding in cooperative relay networks is investigated and an optimized transmission scheme utilizing retransmission is presented. By user data retransmission and optimized power allocation, the system capacity can be improved theoretically. And by comparing with traditional cooperative network coding in a simple two-user scenario, the proposed scheme shows better system performance.