关键词: 协作通信, 中继选择, 译码转发, 门限比较, 功率分配

Abstract: Relay selection is a key problem in the field of cooperative communications, especially for mobile devices using battery to supply power. Different from the relay selection algorithm which is based on the instantaneous Channel State Information（CSI） of two hops, the proposed algorithm which is called threshold comparison algorithm is just based on the instantaneous CSI of the first hop. In this algorithm, a predetermined threshold is set at the relay node and is compared with the Signal-to-Noise Ratio（SNR） between source and relay node. The optimal relay is selected. This paper analyzes the output SNR at the suboptimal relay node theoretically. The simulation results show that the proposed algorithm can achieve similar performance compared with the former algorithm which is based on the instantaneous CSI of two hops. However, it simply considers the instantaneous CSI between the relay node and the source node, so the relay power consumption as well as the complexity of the algorithm is greatly reduced.

Key words: cooperative communications, relay selection, decode-and-forward, threshold comparison, power allocation