基于信道相关性的物理层安全性能分析

Performance analysis of physical layer security based on channel correlation

针对物理层安全研究中主窃信道具有相关性的场景,研究了主窃信道间的相关性对系统安全性能产生的影响,推导得到了遍历保密容量及中断概率的精确计算式,以及主窃信道的信道状态差异较大和较小这2种场景下的渐近计算式,并通过仿真验证了理论分析的正确性。研究结果表明,信道相关性会造成遍历保密容量的损失,但信道相关性强并不一定表明通信中断概率大。当目标速率设置合理时,信道相关性的影响与接收端平均信噪比有关,在高信噪比区域,强相关性会降低中断概率;在低信噪比区域,强相关性会增大中断概率;在中信噪比区域内,相关性几乎不影响系统的中断概率。基于上述结论,可以根据接收端信噪比、信道增益比、相关性等条件合理地设置系统参数,维护系统的安全性能。

In view of the correlation of the main and eavesdropper’s channels in physical layer security,the impact of channel correlation on the secrecy performance was studied,the exact form ulations of ergodic secrecy capacity and secrecy outage probability were derived,and then the asymptotic formulations in the scenarios where the channel states were large and small were given.The theoretical analysis were verified by the numerical simulations.The simulation results show that channel correlation will cause the loss of ergodic secrecy capacity,however,it does not mean the outage probability of communication will increase with high channel correlation.Actually,when the outage rate is set reasonably,the impact of channel correlation is related to the average signal-to-noise ratio(SNR)at the receiver end.At high SNR range,high correlation will decrease the outage probability,at low SNR range,high correlation will increase the outage probability,and at medium SNR range,the correlation will not affect the outage probability significantly.Based on the above conclusion,the parameters can be set according to SNR and correlation,so that the secrecy performance can be maintained.