γ约束均方误差下的无线信道加密方法

A Wireless Channel Encryption Method with γ Mean Square Error

无线信道的开放性和电磁信号的广播特性对无线通信系统的安全提出了极大挑战.无线信道引入的安全问题还需要从无线信道本身加以根本解决.现有基于无线信道的物理层安全方法大多利用了多天线带来的空间冗余,无法应用于单天线点对点的场景.为此,本文首先提出了γ约束均方误差的概念,通过放宽授权用户的最佳线性接收条件在发送端引入预编码权值的冗余.在此基础上将物理层安全问题转变为发送信号随机化问题,并给出了具体分析和相应的理论推导.然后利用无线信道特征的短期可逆性、快速去相关性提出一种全新的物理层加密方法.分析和仿真结果表明,该方法在保证授权用户无条件正常接收的同时大大降低了信号被非法用户截获的概率.

The design of secure wireless communication suffers a great challenge for openness of wireless channel and the broadcast nature of radio signals. The security problem introduced by wireless channel may be solved adequately by wireless channel itself. The space redundancy is often used in existing physical-layer security method to enhance security. So the concept of γ mean square error is proposed in the paper, which is used to introduce redundancy for pre-coding weight. The concrete analysis and corre- sponding formal derivations are also given in the paper. Based on these, a novel physical-layer encryption method is proposed ac- cording to short-term reciprocity, rapid Deecomelation of wireless channel. Simulation results show that the proposed method guaran- tees wireless transmission in the authorized receiver and reduces the probability of interception.