无线通信由于自身传输信道的开放性, 其安全问题相对于有线通信更为突出。物理层安全技术利用无线通信信道天然的多径时变特性, 可为无线传输提供物理层加密, 因而近年来得到快速发展。针对传统物理层安全中密钥生成速率低、频分双工系统不适用等问题, 提出了一种基于信道特征参数的无线通信密钥生成方法。基于宽带信号对多径的辨识力, 利用各径间相对时延生成初始密钥, 结合码本进行密钥长度扩展, 从而生成最终密钥。通过数值分析证明, 相对于传统物理层密钥生成方式, 所提方法能显著提高密钥生成速率, 同时, 基于时延信道特征的互易性, 该方法可适用于时分双工和频分双工无线通信系统的物理层加密。

Due to the openness of propagation channel, the security problem in the wireless communication systems is more serious than that in the wired communication systems. Physical layer security technology adopts the time-variant multipath characteristic of wireless communication channel to ensure security transmission in physical layer. Thus, the physical layer security technology has been developed rapidly in recent years. Traditional physical layer security technologies can just provide low key generation rate, and it cannot be applied to frequency division duplex systems. A scheme of key generation based on channel characteristics is proposed. Based on the multipath identification of wideband signal, this scheme utilizes relative time delays between paths to generate initial key. Then, the length of initial key is extended to generate the final key. The numerical analysis shows that compared with the traditional physical layer key generation scheme, this scheme can significantly improve the key generation rate. And because of the reciprocity of multipath delay, this scheme can be applied to the physical layer encryption of both the Time Division Duplex(TDD) and Frequency Division Duplex(FDD) wireless communication systems.