Weighted Sum-Rate Maximization for STAR-RISs-Aided Networks With Coupled Phase-Shifters

In this letter, we investigate the optimization in a simultaneously transmitting and reflecting reconfigurable intelligent surface-enabled network with a coupled coefficient model, where the transmit beamforming (BF) and the transmitting and reflecting coefficients (TRCs) are jointly designed. Our goal is to maximize the weighted sum rate for multiple users, subject to the discrete coefficient constraint. To solve the nonconcave objective, we develop an alternating optimization method, where the BF can be obtained in a closed form by the bisection method, and the TRCs are solved by the elementwise optimization approach. Simulation results demonstrate the superiority of the proposed algorithm.