Joint Hybrid Precoder and RIS Design for RIS-Aided MIMO-OFDM Systems

To further improve the performance of millimeter wave (mmWave) communications, the reconfigurable intelligent surface (RIS)-aided hybrid precoding has been studied in recent years. Following this direction, we in this paper study the joint hybrid precoder and RIS design for RIS-aided multiple-input multiple-output (MIMO)-orthogonal frequency division multi-plexing (OFDM) systems. We consider two types of the phase shifters which have infinite or finite resolution, and formulate the joint design problem. Designs that can jointly optimize the hybrid precoder and RIS for two types of phase shifters are then respectively proposed. Simulation results show that our proposed designs can outperform the reference design and the design in the literature.