Visual Path Improvement of mmWave MIMO Communications Through a RIS-Equipped Vehicle

This letter presents a reconfigurable intelligent surface (RIS)-equipped vehicle model to help improve the visual paths of millimeter-wave (mmWave) multiple-input and multiple-output (MIMO) communications. As obstacles disrupt the connections between a base station and its users, in this letter we propose a RIS-equipped vehicle to mitigate the interruptions of obstacles and enrich the service area. We set a RIS on the roof of a vehicle and use it in the MIMO mmWave systems to improve the visual paths and serve several single-antenna users efficiently. To verify the superiority of the channel estimation performance, we also propose a multiple RIS-assisted channel (m-RISC) model and employ an orthogonal matching pursuit (OMP) algorithm in this letter. The simulation result shows the achievable sum rate and the normalized mean squared error performance of the proposed m-RISC model, which outperforms the single RISC (s-RISC) model.