Multi-Intelligent Reflecting Surface-Aided Wireless Network With Achievable Rate Maximization

Intelligent reflecting surface (IRS) is a promising technology for improving the rate and energy efficiency of the wireless network. In this paper, we study a multiple-RIS-aided multiple-input multiple-output (MIMO) downlink system, where multiple IRSs are applied to assist the communication between a base station (BS) and a single-antenna user. The objective of this paper is to maximize the achievable rate at the user by jointly designing the active beamforming at the BS and the passive phase shift vector at the multiple IRSs. We utilize an alternate optimization method to obtain the optimized solution. Simulation results show that we can get an excellent performance of the achievable rate by using the proposed multiple-RIS-aided downlink MIMO transmission.