同频干扰环境下双向AF中继性能分析及参数优化

摘要

双向中继（two-way relaying，TWR）作为提高中继网络频谱效率的一种有效手段，近年来受到广泛关注。本文研究同频干扰环境下三时隙TWR策略的中断概率性能，中继采用放大转发（amplify-and-forward，AF）策略。首先，理论推导了策略中断概率下界的闭合表达式和高信噪比下的渐进表达式。仿真表明，理论结果能够匹配策略的实际中断概率性能。根据理论结果，以最小化中断概率为目标对中继节点功率分配和中继位置参数进行优化。提出三种优化问题，即（1）给定中继位置，中继功率分配优化问题，（2）给定中继功率分配方案，中继位置优化问题，（3）联合优化中继功率分配和中继位置。仿真结果表明，联合优化能够实现最优的中断概率性能。%Recently,two-way relaying (TWR)has received much attention as a powerful approach to improve the spectral ef-ficiency of the relaying networks.In this paper,the outage performance of three-time-slot TWR protocol with co-channel interfer-ence was analyzed,where the relay adopts the amplify-and-forward protocol.The lower bound and asymptotic expressions of out-age probability were derived in closed-form and were shown to provide a good approximation to the exact performance.With the theoretic results,the power allocation at the relay and relay location were optimized in order to minimize the outage performance. Three optimization problems were proposed,i.e.,(1 )the optimal power allocation at the relay with fixed relay location,(2)the optimal relay location with fixed power allocation at the relay,(3)joint optimization of power allocation at the relay and relay lo-cation.The results show that the joint optimization scheme can achieve the best performance.