中文摘要：

本文研究在解码转发协作分集中的功率分配问题.本文首先建立了功率分配问题的数学模型,其能够在满足一定平均误比特率的前提下,使源节点和伙伴节点的发射功率之和最小化,从而不仅能够开发多用户无线系统所固有的空间分集能力,而且能够降低移动节点的能耗和网络中的同道干扰.本文还推导了伙伴节点和目的节点的平均误比特率公式,用于刻画在多径衰落中协作分集系统的性能.利用平均误比特率公式,本文提出了一种分布式的功率分配算法,能够使源节点、伙伴节点和目的节点逐个消息地计算最优的功率分配方案.本文所提出的算法不仅具有较小的控制协议开销,而且对信道状态的变化具有自适应能力.因此,该算法能够适应分布式的和动态的无线网络环境.最后,本文通过仿真验证了所提出的算法.

英文摘要：

In this paper,we study the power allocation problem in decode-and-forward cooperative diversity systems.We first present the mathematical model of the power allocation problem,which can minimize the total power consumption of the source and partner under the average bit error rate（BER） constraints at the partner and the destination.Accordingly,the model not only can exploit the inherent spatial diversity in multiuser wireless systems,but also can reduce both the energy consumption of mobile nodes and the cochannel interference in wireless networks.We then derive the BER expressions at the partner and the destination which can characterize the performance of cooperative diversity systems over multipath fading channels.According to the expressions,we propose a distributed power allocation algorithm by which the source,the partner and the destination can compute the optimal power allocation scheme（OPAS） on a message-by-message basis.The proposed algorithm not only has little overhead but also adapts to the changes of channel state.Therefore,the algorithm can conform to the decentralized and dynamic nature of wireless networks.In addition,we present simulations to confirm the proposed algorithm.