Efficient Spectral Efficiency Maximization Design for IRS-aided MIMO Systems

TL;DR

This paper proposes an efficient algorithm for maximizing spectral efficiency in IRS-assisted MIMO systems by jointly optimizing transmit precoding and IRS phase shifts, outperforming existing methods.

Contribution

Introduction of the ADMM-APG algorithm that efficiently solves the non-convex spectral efficiency maximization problem in IRS-MIMO systems.

Findings

ADMM-APG outperforms benchmark methods in spectral efficiency.

The algorithm achieves lower computational complexity.

Significant performance gains across various system setups.

Abstract

Driven by the growing demand for higher spectral efficiency in wireless communications, intelligent reflecting surfaces (IRS) have attracted considerable attention for their ability to dynamically reconfigure the propagation environment. This work addresses the spectral efficiency maximization problem in IRS-assisted multiple-input multiple-output (MIMO) systems, which involves the joint optimization of the transmit precoding matrix and the IRS phase shift configuration. This problem is inherently challenging due to its non-convex nature. To tackle it effectively, we introduce a computationally efficient algorithm, termed ADMM-APG, which integrates the alternating direction method of multipliers (ADMM) with the accelerated projected gradient (APG) method. The proposed framework decomposes the original problem into tractable subproblems, each admitting a closed-form solution while maintaining low computational complexity. Simulation results demonstrate that the ADMM-APG algorithm consistently surpasses existing benchmark methods in terms of spectral efficiency and computational complexity, achieving significant performance gains across a range of system configurations.