NOMA系统的被动中继选择策略

Reactive relay selection strategy for NOMA systems

非正交多址接入技术能够实现更高的频谱利用率、更大的吞吐量和更低的传输延迟,因此被认为是5G网络中多址接入的重要技术之一。为提高非正交协作系统的中断性能,针对非正交多址接入系统的下行链路场景,设计了基于解码转发协议的分布式被动中继选择方案,推导了系统中两用户各自中断概率的闭式结果和高信噪比下的近似结果,最后通过仿真分析得出了中继位置、信道质量和中继个数对系统中断概率的影响规律,并与部分中继选择策略作对比,验证了所提被动中继选择策略的性能优势。

Non-Orthogonal Multiple Access is considered to be a promising candidate for 5G multiple access schemes due to its superior spectral efficiency,higher throughput,and lower transmission delay.To improve the outage performance of non-orthogonal cooperative systems,non-orthogonal multiple access system is studied in the downlink scenario.First,a distributed reactive relay selection scheme based on the decode-and-forward protocol is designed.Then,the closed-form results of the exact outage performance and the approximate results in a high signal-to-noise ratio of the two users are derived.Finally,the effects of the relay position,channel quality and relay number on the outage probability of the system are analyzed by simulation.At the same time,compared with the partial relay selection strategy,the performance advantage of the proposed reactive relay selection strategy is verified.