中继协作下认知NOMA网络性能分析

把非正交多址接入（NOMA）技术应用到认知网络中，提出基于中继协作的底层认知NOMA系统模型。在瑞利衰落信道下，考虑一个两跳的通信网络，认知中继同时接收来自主网络发射源和次网络发射源的信号，并采用串行干扰消除策略解码转发接收到的信号。次级网络通过为主网络提供中继解码转发服务，获得接入授权频段的机会；主网络通过贡献出授权频段，换取次级网络协作通信的机会，同时获得了优先解码权，保证了主网络通信的可靠性。推导了系统各个接收端的中断概率闭合表达式，并进行了MATLAB仿真。仿真结果表明:采用中继协作可以有效提升认知NOMA网络的中断概率性能。 

Performance Analysis on the Cognitive NOMA Network based under Relay Cooperation

The non-orthogonal multiple access (NOMA) technology was applied to cognitive networks, and an underlay cognitive NOMA system model based on relay cooperation was proposed. Under the Rayleigh fading channel, considering a two-hop communication network, the cognitive relay could receive signals from the primary network transmitter and the secondary network transmitter, and applied the successive interference cancellation technology to decode-and-forward the signals it received. The secondary network got the opportunity to access the authority spectrum through providing decode-and-forward service for primary network. The primary network obtained the opportunity for secondary network cooperative communication by providing the authorized frequency band for the secondary network, similarly it got the priority decoding right, which ensuring the reliability of the communication. Closed expression of the outage probability was derived and simulated by MATLAB. The simulation results show that relay cooperation can effectively improve the outage probability performance.