关键词: 协作分集, 放大转发, 中继选择, 误码率, 功率分配

Abstract: Concerning the problem between the optimality and efficiency of the relay selection algorithm, an algorithm of the relay selection based on fast symbol error probability was proposed in Amplify-and-Forward (AF) cooperative networks. First, with the equal power allocation, and based on the statistic channel information and symbol error probability of the system, an equivalent channel gain was brought in. The parameter described the compositive channel character of two phases that were the source node to relay node as well as relay node to the destination in the cooperative process. Then with the descending order of the parameter, the Signal-to-Noise Ratio (SNR) could be taken as the threshold, and different relay node set was chosen to minimize the symbol error probability in case of equal power allocation. And combined with the near optimal power allocation, the proposed scheme further reduced the symbol error probability. As shown in the simulation results, the error probability performance of this relay selection scheme is similar to the optimal full-search scheme but the complexity is reduced to at least 1/20 of the latter one. And it also shows that the error probability of the proposed scheme is lower than the other schemes such as all participating amplify-and-forward (AP-AF) relay selection and pre-select single relay amplify-and-forward (S-AF) relay selection.

Key words: cooperative diversity, Amplify-and-Forward (AF), relay selection, symbol error probability, power allocation