Cascaded Channel Estimation for RIS Assisted mmWave MIMO Transmissions

TL;DR

This paper introduces a novel cascaded channel estimation method for RIS-assisted mmWave MIMO systems that reduces pilot overhead by transforming the problem into parameter recovery and employing advanced algorithms.

Contribution

It proposes a wideband channel estimation framework using Newtonized orthogonal matching pursuit, addressing high pilot overhead in RIS-assisted mmWave MIMO systems.

Findings

Effective channel estimation with reduced pilot overhead

Achieves near the Cramer-Rao lower bound

Numerical results confirm scheme's effectiveness

Abstract

Channel estimation is challenging for the reconfigurable intelligence surface (RIS) assisted millimeter wave (mmWave) communications. Since the number of coefficients of the cascaded channels in such systems is closely dependent on the product of the number of base station antennas and the number of RIS elements, the pilot overhead would be prohibitively high. In this letter, we propose a cascaded channel estimation framework for an RIS assisted mmWave multiple-input multiple-output system, where the wideband effect on transmission model is considered. Then, we transform the wideband channel estimation into a parameter recovery problem and use a few pilot symbols to detect the channel parameters by the Newtonized orthogonal matching pursuit algorithm. Moreover, the Cramer-Rao lower bound on the channel estimation is introduced. Numerical results show the effectiveness of the proposed channel estimation scheme.