基于同频同时全双工自干扰消除的有线保密通信系统

针对目前有线全双工通信系统中保密通信技术尚未成熟，在保密性能存在局限性，以同频同时全双工(co-frequency co-time full duplex, CCFD)系统的自干扰(self-interference, SI)消除理论为基础，提出一种物理层绝对安全的有线保密通信系统设计方案，通过巧妙地在接收端向链路中释放同时同频大功率人造噪声的方式将目标信号隐藏起来，再利用接收机对噪声信号的已知性，借助CCFD系统的模拟域自干扰消除技术在接收机中实现高dB的SI消除，实现Wyner意义上的绝对安全的保密通信。依据香农理论分析了延迟时间差、窃听位置、传输线长度等因素对SI消除能力和系统安全容量的影响。结果表明：系统的安全容量始终大于零，达到绝对保密通信效果。

Wire-Line Secure Communication System Based on CCFD Self-Interference Cancellation

For the current wired full duplex communication system in the confidential communication technology has not matured, in the confidentiality performance there are limitations. A design scheme of the wired secure communication system with absolute security in the physical layer has been presented, which is based on the self-interference (SI) cancellation theory of the co-frequency co-time full duplex(CCFD) system. The target signal is hidden by skillfully releasing simultaneous same-frequency high-power artificial noise into the link at the receiver end, and then using the receiver''s known noise signal to achieve high dB SI cancellation in the receiver with the help of the analog domain SI cancellation technology of the CCFD system to achieve absolutely secure and confidential communication in the Wyner sense. The effects of delay time difference, eavesdropping location, transmission line length and other factors on SI cancellation capability and system security capacity are analyzed based on Shannon theory. The research work shows that the security capacity of the system is always greater than zero, achieving the effect of absolute confidential communication.