双向中继ARQ的机会网络编码和信号合并

ARQ-based Opportunistic Network Coding and Signal Combining strategy for Two-Way Relay Network

为了提高双向中继网络(TWRN)的系统有效性和可靠性,提出了一种基于自动重传请求协议(ARQ)的机会网络编码和信号合并策略(ONCSC)。假设中继节点带有缓存器,能够存储接收信号,中继节点对接收到的不同时隙信号进行合并,并根据最大似然(ML)检测结果决定下一个时隙是接收还是发送信息。同时,提出两种中继合并方法——最大和信噪比合并(MS-SNR)和最大最小信噪比合并(MM-SNR)。通过仿真,相比不加ARQ和不加合并的ARQ方案,提出的两种合并方法丢包率较低,在中等信噪比时有吞吐量的提升,也得到了期望的性能增益。

For improving throughput and reliability of the two-way DF（decode-and-forward） relay networks, an ONCSC（opportunistic network coding and signal combining） strategy based on ARQ（automatic repeat request） protocol is proposed. Assuming that RN（relay node） with buffer can store the received signals, combine the signals received from different time slots and make judgement to transmit or receive in the next time-slot according to the output of ML（maximal likelihood） detector. Two signal combining methods at the RN, that is, MSSNR（maximal sum signal-to-noise ratio combining） and MM-SNR（maximal minimum signal- to-noise ratio combining） are proposed in this paper. Simulation results indicate that the proposed two signal combining methods outperform the traditional No-ARQ and No-combining ARQ systems in PER（packets error ratio） and throughput, and acquire the expected performance gains in moderate SNR. Also the optimal power allocation factors of between the sources and RN in the simulations are discussed.