Channel Estimation for RIS-Aided mmWave MIMO Channels

TL;DR

This paper proposes a two-stage iterative channel estimation scheme for RIS-aided mmWave MIMO channels, achieving high-resolution channel parameter estimation and near-perfect spectrum efficiency.

Contribution

It introduces a novel two-stage iterative estimation method tailored for RIS-assisted mmWave MIMO systems, improving accuracy and efficiency.

Findings

Achieves high-resolution channel estimation.

Provides spectrum efficiency comparable to perfect CSI.

Enhances RIS beamforming gain.

Abstract

A reconfigurable intelligent surface (RIS) can shape the radio propagation by passively changing the directions of impinging electromagnetic waves. The optimal control of the RIS requires perfect channel state information (CSI) of all the links connecting the base station (BS) and the mobile station (MS) via the RIS. Thereby the channel (parameter) estimation at the BS/MS and the related message feedback mechanism are needed. In this paper, we adopt a two-stage channel estimation scheme for the RIS-aided millimeter wave (mmWave) MIMO channels using an iterative reweighted method to sequentially estimate the channel parameters. We evaluate the average spectrum efficiency (SE) and the RIS beamforming gain of the proposed scheme and demonstrate that it achieves high-resolution estimation with the average SE comparable to that with perfect CSI.