Power Allocation Algorithm Minimizing Outage Probability in Cognitive Radio Relay Network
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.