中文摘要：

频谱共享的Underlay认知中继网络中,为了保证主用户的可靠通信,要求次用户网络中源节点及中继节点的发射功率必须满足主用户接收端干扰功率的限制。基于主用户峰值干扰功率和平均干扰功率的联合限制,分析了中继节点采用选择协作解码转发协议时潜伏式频谱共享认知中继网络的性能。值得一提的是,考虑中继传输中由主用户接收端干扰功率限制引起的第1跳链路信噪比之间的相关性,推导了瑞利衰落环境下次用户中断概率和信道容量准确的闭合表达式。仿真结论显示,次用户中断概率与信道容量的解析曲线与仿真结果一致,系统性能因频谱共享的认知网络中次用户源节点与主用户接收机链路之间的相关性而有所下降,中断概率约有2dB的性能提升。

英文摘要：

To guarantee the reliable communications of the primary user（PU）in cognitive relay networks under underlay spectrum sharing constraints,the transmission powers of the secondary source and relays must satisfy the needs of the interference power constraints at the PU receiver.With both peak and average interference power limits,the paper analyzes the performance of selection cooperative decode-and-forward（DF）relaying in underlay cognitive relay networks.Particularly,taken the correlations among the received signal to noise ratios（SNRs）of the first hop in the relaying transmission caused by interference power constraint imposed by the primary receiver into account,the paper derives exact closed-form expressions for the outage probability and channel capacity of the secondary user（SU）under condition of Rayleigh fading channels.The simulation results show that the analytical outcomes of the outage probability and channel capacity match well with the simulation results,the performance of the SU is degraded dueto the dependence of the links between the SU source and the PU receiver in the context of cognitive radio environment with spectrum sharing constraints.Importantly,the consideration of the correlations improves the system performance as much as 2dB.