认知无线中继网络最小化中断概率功率分配算法

摘要

为提升认知无线中继网络的中断性能,通过分析系统中断概率及用户功率分配情况,提出一种最小化中断概率的功率分配算法.给出在主用户干扰约束和总功率约束条件下最小化中断概率的数学优化方程组,根据用户的最大发射功率与干扰电平阈值的受限关系,分别考虑分配功率不超过干扰电平阈值、中继节点功率受限于干扰电平阈值以及所有节点受限于干扰电平阈值这3种情况,对应提出3种最佳功率分配方案,并基于KKT条件求解最优值.实验结果表明,该功率分配算法与基于频谱共享以及基于机会主义中继选择的中断概率分析方法相比,性能增益提升显著,并且在总功率、干扰电平变化的条件下,所采用的功率分配方案提升系统中断性能效果较好.%To improve the outage performance of cognitive radio relay network,this paper proposes a power allocation algorithm minimizing outage probability by analyzing the system outage probability and user power allocation conditions.It presents the mathematical optimization equations minimizing outage probability of under master user interference constraint and total power constraint.Then,according to the relationship between the user's maximum transmit power and interference level threshold,it proposes three optimal power allocation schemes respectively to deal with three types of cases,including the distribution of power not exceeding the interference level threshold,the relay node power limited by the interference level threshold,and all nodes limited by the interference level threshold.Finally,the optimal value is solved based on Karush-Kuhn-Tucker(KKT) conditions.Experimental results show that compared with similar power allocation methods,the proposed algorithm has obvious performance gain promotion.And the effectiveness of the adopted power allocation schemes is proved the most effective in enhancing the system outage performance when the total power or the interference level is changing.