移动通信系统平均物理层安全容量

Mean physical-layer secrecy capacity in mobile communication systems

为提升移动通信系统的安全性,研究了用户移动时的平均物理层安全容量。在实际传播环境中,用户移动会导致物理层安全容量在大范围内变化,因此提出合法用户平均物理层安全容量以刻画系统的安全通信性能。通过分析窃听者位置对平均物理层安全容量的影响,得到了平均物理层安全容量的分布特征。根据分布特征,提出了一种改善平均物理层安全容量的方案。该方案通过限制窃听者存在区域,保证用户平均物理层安全容量不低于指定值。理论和数值分析结果表明:所提方案可以有效地保障移动通信系统的平均物理层安全容量。

The security of mobile communication systems depends on the mean physical-layer secrecy capacity as the user moves. In realistic propagation environments, the physical-layer secrecy capacity varies over a vast range because of the user motion. A mean physical-layer secrecy capacity of a legitimate user is defined to characterize the secure communication performance of the system. The distribution characteristics of the mean physical-layer secrecy capacity are derived based on the impact of the eavesdropper＇s position on the mean physical-layer secrecy capacity. A scheme is then given to improve the mean physical-layer secrecy capacity according to the distribution characteristics. The mean physical-layer secrecy capacity can be made to be not lower than a specified value by limiting the eavesdropper＇s positions. Theoretical and numerical results demonstrate that this scheme can effectively guarantee the mean physical-layer secrecy capacity in mobile communication systems.