重叠Nakagami-m信道协作通信最优功率分配方案

为了解决重叠Nakagami-m信道衰落模型下中继译码转发协作通信系统中源与中继间由于等功率分配(EPA)造成的功率资源浪费问题,提出了一种基于渐近误符号率(SER)最小准则的最优功率分配方案(OPA).首先分析系统渐进SER解析式,在典型应用场景下对其进行进一步简化,然后将简化的系统SER作为目标函数,总功率受限作为约束条件,将功率资源分配抽象为典型的条件受限凸优化求解问题,最后利用拉格朗日乘数法对此凸优化问题进行求解,从而得出在总功率资源受限时典型场景下重叠Nakagami-m信道协作通信系统的最优功率分配方案.仿真结果表明:相较EPA方案,在较大的信噪比区间内及相同的信道条件下,OPA分配方案均能获得约1 dB的信噪比增益,且获得的实际信噪比增益与理论推导值一致.

An Optimal Power Allocation Scheme for Cooperative Communications Over Double Nakagami-m Fading Channels

An optimal power allocation(OPA) scheme is proposed to solve the power resource waste problem between source and relay nodes for a cooperative communications system with single decode-and-forward relay over double Nakagami-m fading which is caused by equal power allocation(EPA).The proposed scheme bases on minimizing symbol-error-ratio(SER).First,the asymptotic SER is analyzed and then simplified in the so called typical condition.Then,the power allocation problem is formulated as a typical convex optimization problem with the SER as the objective function and the restriction of the sum power as the constrain condition.The Lagrange method is used to solve the optimization problem to obtain the close-form of the optimal power allocation in the so called typical condition.Simulations and comparisons with EPA show that in a big rang OPA can obtain the signal to noise ratio(SNR) gain about 1dB over some channel condition,and that the gain is consistent with the theoretical SNR gain.