Hybrid Beamforming for Intelligent Reflecting Surface Aided Millimeter Wave MIMO Systems

TL;DR

This paper proposes a joint design of IRS reflection and hybrid beamforming for mmWave MIMO systems, demonstrating significant spectral efficiency improvements for both narrowband and broadband scenarios.

Contribution

It introduces a novel joint design approach leveraging channel sparsity for IRS-assisted mmWave MIMO systems, applicable to both narrowband and broadband cases.

Findings

Joint design improves spectral efficiency substantially.

Proposed methods outperform existing designs.

Effective for both narrowband and broadband systems.

Abstract

As communication systems that employ millimeter wave (mmWave) frequency bands must use large antenna arrays to overcome the severe propagation loss of mmWave signals, hybrid beamforming has been considered as an integral component of mmWave communications. Recently, intelligent reflecting surface (IRS) has been proposed as an innovative technology that can significantly improve the performance of mmWave communication systems through the use of low-cost passive reflecting elements. In this paper, we study IRS-aided mmWave multiple-input multiple-output (MIMO) systems with hybrid beamforming architectures. We first exploit the sparse-scattering structure and large dimension of mmWave channels to develop the joint design of IRS reflection matrix and hybrid beamformer for narrowband MIMO systems. Then, we generalize the proposed joint design to broadband MIMO systems with orthogonal frequency division multiplexing (OFDM) modulation by leveraging the angular sparsity of frequency-selective mmWave channels. Simulation results demonstrate that the proposed joint designs can significantly enhance the spectral efficiency of the systems of interest and achieve superior performance over the existing designs.