RIS-Aided Multiple-Input Multiple-Output Wireless Communication System Considering Hardware Impairments

Reconfigurable intelligent surface (RIS) has become a crucial technology for the next generation wireless communication due to its good performance on low power consumption and high energy efficiency. In this paper, we investigate maximizing the sum of achievable data rates (SADR) of all the users by considering hardware impairments in the RIS-aided multiple-input multiple-output (MIMO) wireless communication system. Owing to the coupling effect of the multiple variables of the optimization problem (OP), we adopt the block coordinate descent algorithm (BCDA) to decouple the original problem into two sub-problems where the transmitting precoding matrix (TPM) and phase shifts are alternately optimized. Specifically, the upper bound optimal solution of the TPM can be obtained in closed form through the Lagrangian multiplier method, and majorization-minimization algorithm (MMA) is applied to solve the sub-problem of optimizing phase shifts. Simulation results demonstrate the necessity of considering hardware impairments into beamforming optimization and the effectiveness of introducing RIS into the MIMO system.