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，它是一种通过智能配置反射单元来反射入射信号的新兴技术，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，每个用户接收期望信号。为保证无线通信的公平性，我们需在基站功率约束和IRS相位约束下，最大化用户的最小速率。先前关于IRS的研究主要关注优化基站波束成形和IRS被动波束成形，本文还旨在优化IRS的位置。所考虑的问题被证明是非凸的，我们将其分解为两个子问题，通过将两个子问题转化为下界问题，并分别采用交替优化（AO）和连续凸近似（SCA）进行求解。最后，两个子问题交替优化，使目标函数值在可接受范围内收敛。仿真结果验证了所提算法的收敛性，以及与无线通信系统中基准方案相比的性能提升。