卫星通信系统的物理层安全性能分析

Analysis of physical layer security performance for satellitecommunication systems

由于全球卫星通信系统信道完全开放、天地一体化组网等,导致其通信安全保障面临严峻挑战。而物理层内生的安全机制能够保障卫星通信安全,有效地防止信道窃听。结合天地一体化组网,构建了同时存在地面窃听基站和窃听卫星场景的卫星通信系统安全性能分析框架。基于瑞利衰落信道和Shadowed-Rician衰落信道,分别建立了两类窃听者的窃听模型;考虑窃听者采用不共谋策略和共谋策略,分别推导出了两种窃听策略下该系统的平均安全容量和安全中断概率的解析表达式,以评估系统的物理层安全性能。仿真结果表明,提高发射功率能够保证在安全中断概率不变的情况下有效地提高系统的安全容量。与地面窃听基站相比,降低窃听卫星处的信噪比能够更显著地提高系统的安全性能。

Due to the openness of the wireless medium and construction of the space-ground integrated information network,satellite communication(SATCOM)systems are facing severe security challenges.Physical layer security technology can guarantee secure satellite communication and effectively prevent the channel from being eavesdropped.By taking into account the space-ground integrated information network,a security performance analysis framework is developed for the SATCOM system with the existence of a ground eavesdropper and a satellite eavesdropper.Based on the Rayleigh fading channel and Shadowed-Rician fading channel,eavesdropping models of two eavesdroppers are provided,respectively.Regarding the non-collusion and collusion strategies employed at eavesdroppers,the exact expressions for average secrecy capacity(ASC)and secrecy outage probability(SOP)are derived under the two strategies,respectively.Simulation results show that a growing transmit power can improve ASC with SOP unchanged at the same time.Reducing the signal noise ratio at the satellite eavesdropper can provide a better secrecy performance for the SATCOM system than decreasing the signal noise ratio at the ground eavesdropper.