Passive Beamforming for Practical RIS-Assisted Communication Systems With Non-Ideal Hardware

Abstract

Reconfigurable intelligent surface (RIS) technology is a promising solution for enhancing the performance of existing wireless communication systems. To achieve its advantage of cost-effectiveness, there inevitably exist certain hardware impairments in the system, leading to severe performance degradation. Some existing works have considered such problems under transceiver hardware impairments but neglected the practical model of RIS. Moreover, their performance still leaves room for improvement. To address these issues, RIS passive beamforming is re-optimized in this paper to maximize spectrum efficiency, taking into account both transceiver hardware impairments and practical RIS model. We deal with the fractional structure of the problem by using the quadratic transform. The remaining sub-problems are addressed utilizing the penalty-based method and the difference-of-convex programming. Since all sub-problems have closed-form solutions, our method is highly efficient. Numerical results demonstrate the superiority of our method. Most importantly, our solution reduces unnecessary resource consumption in practical scenarios.