放大转发中的最优功率分配与最佳中继选择

Optimal power allocation and relay selection in amplify-and-forward relay systems

用最优功率分配与最佳中继选择相结合的方法实现了放大转发系统的误比特率最小化。为了使单中继非协作放大转发系统的误比特率最小,通过分析媒体接入控制(MAC)层的请求发送/允许发送(RTS/CTS)信息,获得候选中继前向信道和后向信道的增益,以信道增益为变量,得到最佳功率分配的闭合表达式。同时,以误比特率作为中继选择准则,实现分布式最佳中继选择。仿真结果表明,与同类算法相比,该功率分配与中继选择策略使系统的误比特率达到最小。

The minimization of the bit error rate （BER） of amplify-and-forward relay systems was achieved using the method of combining the optimal power allocation with the optimal relay selection. In order to minimize the BER of a single-relay non-cooperative amplify-and-forward system, the forward-channel gain and the backward-channel gain at the candidate relay were obtained through analyzing the request to send/clear to send （RTS/CTS） information in the medium access control （MAC） layer, and a closed form expression to allocate power optimally was got, which is the function of the channel gain. At the same time, considering the BER as the relay selection criterion, a distributed method to select the best relay was presented. The simulation results show that when using the proposed strategy, the system BER is the smallest compared to other similar methods.