Abstract:

In view of the fact that most of physical layer security research does not consider the impact of channel estimation error on security performance at present, a full-duplex two-way relay network security performance based on imperfect Channel State Information（CSI） is studied. It is assumed that there are no direct links between users in the system at first, and that CSI cannot be obtained. The optimal relay selection scheme is adopted, and the expressions of system security capacity and Secrecy Outage Probability（SOP） are derived according to the principle of maximum and minimum. Further, the main factors affecting the secrecy performance of the system are analyzed, and the performance difference between full-duplex and half-duplex systems is compared. The simulation results show that the system secrecy performance is best when the relay node is at the midpoint between users. Meanwhile, reducing the channel estimation error, the average signal-to-noise ratio of the eavesdropping link and the residual self-interference can effectively reduce the system SOP, and appropriately increasing the number of relays can obtain better security performance.

Key words: full-duplex, optimal relay selection, channel estimation error, Secrecy Outage Probability（SOP）

摘要：

针对目前物理层安全研究大多未考虑信道估计误差对安全性能的影响，研究基于非理想信道状态信息（Channel State Information，CSI）的全双工双向中继网络安全性能。假设系统中用户之间没有直连链路，且无法获取CSI；采用最优中继选择方案，选取最优中继将信号进行解码转发至目的端；根据最大最小原则推导出系统安全容量和保密中断概率（Secrecy Outage Probability，SOP）的表达式，进一步分析影响系统保密性能的主要因素，并对比全双工与半双工系统性能的差异。仿真结果表明，当中继节点处在用户间的中点位置时，系统保密性能最好；同时，减小信道估计误差、窃听链路的平均信噪比及剩余自干扰能够有效降低系统SOP，适当地增加中继数目可以获得更好的安全性能。

关键词: 全双工, 最优中继选择, 信道估计误差, 保密中断概率