STAR-RIS Assisted Millimeter Wave Massive MIMO NOMA Downlink Secure Network Against Internal and External Eavesdropping

In this paper, we investigate a simultaneously trans-mitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted millimeter wave (mm Wave) massive multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) security networks. The network considers both internal and external eavesdropping, with legitimate users, external eaves-droppers, and internal eavesdroppers distributed on both sides of the STAR-RIS, and a hybrid beamforming architecture for both the transmitter and the receiver. Our objective is to maximize the system sum secrecy rate under the QoS constraint of users, base station transmits power constraint, constant modulus constraint, STRA-RIS amplitude coefficient and phase shift constraints. Con-sidering the complexity of the proposed optimization problem, we establish an optimization constraint model based on the penalty function method. By employing a heuristic algorithm to address the fitness function, we obtain an optimal solution to the nonconvex problem after iterations. Simulation results validate the effectiveness of our proposed method.