基于信道弱特征随机加扰的宽带系统物理层加密算法

针对无线宽带系统面临的窃听问题，提出一种基于信道时域弱特征随机加扰的物理层加密算法. 发送用户利用特征值分解将非奇异的授权用户信道特征矩阵分解成多个并联子信道，然后选择具有强特征的子信道发送有用信息，将具有弱特征的子信道转化为快时变信道，使授权用户接收信号趋于稳定，窃听用户接收信号质量恶化. 仿真结果表明，该算法通过特征选取可降低对授权用户的信道要求，同时降低窃听用户的SINR使窃听保持较高的误码率，从而提高系统安全性.

Physical Layer Secrecy of Wideband System by Adding Random Noise Based on Channel’s Weak Characteristics

To combat wiretapping of wireless wideband system, this paper presents a method for wireless wideband system physical layer secrecy in the time domain. The method adds random noise based on weak channel characteristic. First, the transmitter decomposes the nonsingular channel characteristic matrix into
some sub-channels. The sub-channels with strong characteristic are selected to transmit useful information, and weak ones are transformed into a random channel. The signal received by legitimate receivers becomes steady, while the eavesdropper’s turns random. Simulation results show that the method can lower the requirements to the legitimate channel state while decrease SINR at eavesdroppers to keep its error probability high so as to enhance system security.