全双工主动窃听非正交多址接入系统智能超表面辅助物理层安全传输技术

Reconfigurable Intelligent Surfaces-aided Physical Layer Secure Transmission in Non-Orthogonal Multi-Access Systems Against Full-duplex Active Eavesdropping

针对全双工被动窃听和主动干扰攻击下的多用户非正交多址接入(NOMA)系统,该文提出一种智能超表面(RIS)辅助的鲁棒波束赋形方案以实现物理层安全通信。考虑在仅已知窃听者统计信道状态信息的条件下,以系统传输中断概率和保密中断概率作为约束,通过联合优化基站发射波束赋形、RIS相移矩阵、传输速率和冗余速率,来最大化系统的保密速率。为解决上述多变量耦合非凸优化问题,提出一种有效的交替优化算法得到联合优化问题的次优解。仿真结果表明,所提方案可实现较高的保密速率,且通过增加RIS反射单元数,系统保密性能更佳。

Considering the multi-user Non-Orthogonal Multi-Access(NOMA)system under the full-duplex attack of passive eaves-dropping and active interference at the same time,a robust beamforming scheme based on Reconfigurable Intelligent Surfaces(RIS)is proposed to realize physical layer secure communication.Under the condition that only the channel state information of the eavesdropper is known,the system transmission interruption probability and the confidential interruption probability are taken as the constraints and the system confidentiality rate is maximized by jointly optimizing the base station transmission beamforming,RIS phase shift matrix,transmission rate and redundancy rate.In order to solve the above multivariate coupling non-convex optimization problem,an effective alternating optimization algorithm is proposed to obtain the suboptimal solution of the joint optimization problem.The simulation results show that the proposed scheme can achieve a higher confidentiality rate,and when the number of RIS reflective elements is increased,the system confidentiality performance gets better.