主用户链路深度衰落下的认知网络中继

Cognitive radio network relay for primary users under deep fading conditions

针对主用户链路经历深度衰落而发生通信中断的问题,提出了一种认知网络对主用户进行'透明'中继的方案。在不改变主用户通信协议的前提下,该方案首先感知主用户的状态,以判断其是否需要中继服务。当主用户通信发生中断时,认知网络利用从用户的能量检测器选出一个最优的节点解码转发主用户信号。从中断概率角度证明了这种最优单节点中继具有与多节点中继相同的空间分集作用,能够提高主用户平均传输效率,有较大的中继信道容量。通过仿真分析,验证了其分集效果和传输效率的提升。

A transparent relay scheme of cognitive radio network is pmposed to resolve the outage problem of primary user link caused by deep fading. Without altering the communication protocol of primary users, the scheme firstly senses the state of primary users to decide whether they need relay. The best relay node is selected using the energy detector from the cognitive radio network to decode and forward primary users＇ signals if outage happens. It is proved that the single best node relay provides the same spatial diversity as the multi-nodes relay in the term of outage probability. The scheme im- proves the average transmission efficiency of primary users and achieves a high relay channel capacity. The simulation re- sults show its spatial diversity as well as the transmission efficiency improvement.