中文摘要：

提出了选择中继协议下最小化系统中断概率的最优功率分配方案，并给出了最佳功率分配的闭式解。根据协作节点间是否存在交互信息，分别通过对系统中断概率的分析，推出了高信噪比下中断概率的理论界。基于理论界，在功率受限的情况下，通过拉格朗日乘数法，得到最优功率分配的闭合解。仿真结果表明，所推理论界在高信噪比下与仿真值近似相等，最优功率分配点的系统性能也要优于其他功率分配点。

英文摘要：

An optimal power allocation （OPA） method to mininaize the outage probability of selection relaying protocol is presented. According to whether or not the cooperative nodes can communicate with each other, the outage probability is analyzed in two cases. A tight bound of the outage proba-bility at high signal-to-noise ratio （SNR） is derived. Based on the outage probability analysis, an OPA method is obtained by Lagrange multiplication law. The simulation results show the outage probability bound is tight at high SNR, and the SER performance of the cooperative system with the OPA is better than that of other power allocation methods.