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.

翻译：智能反射面（IRS）近年来被广泛研究，它作为一种新兴技术，可通过智能配置反射单元对入射信号进行反射，从而改变信号传播环境，增强用户期望信号并抑制用户间干扰。本文研究IRS辅助的多用户无线通信系统，其中基站（BS）发送多种信号，各用户接收期望信号。为保证无线通信公平性，需在基站功率约束和IRS相位约束下最大化用户最小速率。现有IRS相关研究主要关注优化基站波束赋形与IRS被动波束赋形，本文还旨在优化IRS位置。所考虑问题被证明是非凸的，我们将原问题分解为两个子问题，并将两个子问题转换为下界问题，分别采用交替优化（AO）和连续凸近似（SCA）进行求解。最终对两个子问题交替优化，使目标函数值收敛至可接受范围内。仿真结果验证了所提算法的收敛性，以及相较于无线通信系统中基准方案的性能提升。