中文摘要：

研究了功率受限情况下多中继协作通信网络的中继选择和功率优化问题。在AF网络中，提出了一种低复杂度中继选择与功率分配算法，其目标是在总功率一定的条件下使系统的中断概率最小。本算法对源节点和所有潜在中继节点进行功率分配，结合当前信噪比选择最优的中继集合，通过最速下降法求出使系统中断概率最低的功率分配因子。该算法不需要知道大量瞬时信道信息、不需要系统在等功率条件下进行中继选择，只需求得中继节点排列矩阵便可根据当前信噪比自适应获得最优中继节点集合。仿真结果表明，在相同条件下，该算法明显优于不同中继节点集合下几种算法的中断性能，并且与传统的SAF及AAF算法相比，有效降低了中断概率，提升了系统性能和功率效率。

英文摘要：

The relay selection and power optimization of multirelay cooperative communication network under a joint sum power constraint was considered. A low complexity relay selection and power allocation algorithm was also pro posed in amplifyandforward cooperative network aiming at minimizing the probability of system outage. In this scheme, optimal power allocation among source and relay nodes was conducted. According to the SNR, an optimal relay node set was selected and a power allocation factor leading to a lower system outage probability was obtained by steepest descent method. This algorithm did not need large quantity of channel statistical information and equal power condition. It can obtain the best set of relay nodes under optimal power allocation only by solving the arranged matrix on the basis of Sig nal to Noise Ratio. Simulation results show that the proposed relay selection and power allocation algorithm, under the same conditions, compared in the outage probability in different relay node set among several algorithms, achieves better performance in outage probability and power efficiency.