非完全信道下认知中继网络中断概率及功率分配

基于最大信道增益的中继选择方法，分析了在不完全信道状态信息（CSI，channel state information）和受主用户干扰情况下认知中继网络的中断概率；进一步提出了在主用户干扰约束和保证认知用户服务质量（QoS，quality of service）条件下最大化认知中继网络频谱效率的数学优化模型，利用拉格朗日对偶松弛法获得了该优化问题的解，在保证主用户传输性能不受影响的前提下，提高了认知中继网络的频谱效率。仿真结果表明该文提出的功率分配方案与等功率分配方案相比提高了性能增益。同时表明在非完全信道条件下获得的频谱效率与完全信道条件下的频谱效率近似，但减少了系统信息的反馈量和实现的复杂度，有利于该方案的工程应用。

Outage probability and power allocation in cognitive relay networks under imperfect channel state information

Considering the interference introduced by primary user, the outage probability of cognitive relay networks under imperfect channel state information is analyzed based, on the relay selection for the maximum channel gain. In addition, the mathematical optimization model of maximizing the spectrum efficiency under the interference constraint of primary user and the QoS requirement of cognitive user is proposed for cognitive relay networks. Then, the optimal solution of the model is obtained with the Lagrangian method. The proposed scheme improves the spectrum efficiency of cognitive relay networks on the premise of guaranteeing the transmission performance of primary user. Simulation results show that the proposed power allocation scheme improves the system performance compared with the traditional equal power allocation scheme. Meanwhile, it indicates that the approximate spectrum efficiency can be obtained under the perfect channel state and the imperfect channel state. Under the imperfect channel state, the feedback information and the complexity of implementation will be reduced, which is beneficial to the engineering application.