基于人工噪声的多用户MIMO系统加密算法

A Multi-user MIMO System Encryption Algorithm Based on Artificial Noise

当多用户MIMO系统中的用户数多于或等于发射端天线数时,现有的基于人工噪声的物理层加密算法会导致合法用户无法正常接收。为提高此时的多用户MIMO系统的安全性,该文提出一种新的基于人工噪声的多用户MIMO系统加密算法。首先,发送端对多个合法用户进行联合处理,建立多用户联合信道状态矩阵;然后,将联合信道状态矩阵进行奇异值分解,并根据最小的奇异值进行预编码,以消除人工噪声对合法用户的影响;最后,提出一种优化功率分配的方案。仿真结果表明,该算法将多用户MIMO系统的保密容量平均增加了0.1 bit/(s Hz),从而提高多用户MIMO系统的安全性。

The existing physical layer encryption algorithm, which is based on artificial noise, could affect legitimate receivers negatively when the number of users is no less than sending antennas in the multiuser MIMO system. In order to improve the multiuser MIMO system security under this scenario~ this paper proposes a new multiuser MIMO system physical layer encryption algorithm based on joint channel state matrix. Firstly, multiple users are processed together, thus a multiuser joint channel state matrix is established. After Singular Value Decomposition （SVD） of the joint channel state matrix, the minimum singular value is obtained and can be utilized for pre-coding, so as to eliminate the interference of artificial noise to legitimate receivers. Farther, the paper also presented an approach to optimize the power allocation. The simulation results show that the proposed algorithm can increase the secrecy capacity by 0.1 bit/（s- Hz） averagely, and improve the multiuser MIMO system security.