基于智能反射表面辅助的MIMO无线通信密钥快速生成

MIMO Fast Wireless Secret Key Generation Based on Intelligent Reflecting Surface

近来,结合智能反射表面(IRS)辅助无线通信的密钥生成技术引发了学界的兴趣。然而目前的工作仅针对在单天线收发(SISO)系统中引入IRS辅助密钥生成,其IRS对密钥生成速率的提升效率不够高。针对此问题,该文研究了基于IRS结合MIMO系统的无线密钥快速生成方案,通过控制IRS反射合法双发与IRS之间的MIMO信号来构建等效的快速信道,可更显著地提升密钥生成速率(KGR)。该文首先从信息论角度对所提方案的密钥速率和安全性进行了分析与证明,推导了密钥速率性能上界的表达式。基于此,从不同的窃听场景出发,分析窃听者分别靠近合法收发方和IRS进行窃听时,其靠近的距离对密钥生成速率性能的影响,发现所提方案在密钥速率和安全性能上均得到显著提升。最后,通过仿真验证了所提方案的有效性和理论分析的正确性。

Recently,there is a growing interest in employing Intelligent Reflecting Surface(IRS)to assist physical layer key generation in wireless networks.However,current works only study the IRS-aided key generation schemes in Single-Input-Single-Output(SISO)communications,which have relatively low promotion of key generation rate.To fill this gap,the IRS-aided Multiple-Input-Multiple-Output(MIMO)key generation scheme is investigated in this paper.By fully exploring the reflection signals at the IRS as the artificial randomness,combined with the MIMO incident signals to build the fast channel,the performance of Key Generate Rate(KGR)can be significantly improved.The information theoretical security and limits of KGR are fully proven,and upper bound expression of KGR performance is derived.Based on this,the security under different eavesdropping attack scenarios are studied,where the eavesdropping attack is launched close to the legitimate transmitter/receiver,and IRS,respectively.It verifies that the proposed scheme improves significantly the KGR and security performance.Finally,the simulations are conducted to verify the proposed scheme and the correctness of theoretical analysis.