Intelligent Reflecting Surface Aided Wireless Communication Systems: Joint Location and Passive Beamforming Design

Intelligent reflecting surface (IRS) has been widely studied in recent years, it has emerged as a new technology which can reflect the incident signal by intelligently configuring the reflection elements, thus changing the signal propagation environment, enhancing the signals users desire and suppressing the interference between users. In this paper, we study an IRS aided multi-users wireless communication where the base station (BS) sends a variety of signals, each user receives desired signals. In order to guarantee the fairness of wireless communications, we need to maximize the minimum rates of users, subject to the power constraint of BS and the phase constraint of IRS. Prior works on IRS mainly consider optimizing BS beamforming and IRS passive beamforming, this paper also aims to optimize the IRS location. The considered problem is shown to be non-convex, we decompose the problem into two subproblems, transforming the two subproblems into a lower bound problem and using alternating optimization (AO) and successive convex approximation (SCA) to solve them, respectively. Finally, the two subproblems are optimized alternately to make the objective function value converge in an acceptable range. Simulation results verify the convergence results of our proposed algorithm, and the performance improvement compared with the benchmark scheme in wireless communication system.