Sum Rate Maximization for RIS-Assisted Hybrid Beamforming Systems.

Reconfigurable intelligent surfaces (RISs) are be-corning a prominent technology for beyond 5G or 6G systems, especially when line-of-sight paths are blocked for the high frequencies with fewer scattering paths. In this paper, we consider a RIS-aided multi-user hybrid beamforming system to enhance the sum rate by jointly constructing analog/digital beamforming and RIS reflection coefficients. A low complexity but efficient algorithm is proposed for finding the reflection coefficients of RIS elements working in conjunction with the conventional 3D hybrid beamforming techniques. Simulation results demonstrate that our scheme can work in various practical environments, providing a good trade-off between the sum rate performance and computational complexity.