Beam-Squint-Aware Parametric Cascaded Channel Covariance Estimation for Reconfigurable Intelligent Surface–Aided Dual- Wideband Multiple-Input Multiple-Output

Abstract

Reconfigurable intelligent surfaces (RISs) have attracted considerable attention in the wireless communications literature for their ability to enhance capacity and coverage by dynamically reconfiguring the electromagnetic propagation environment using low-cost, nearly passive reflective elements. This study introduces a parametric cascaded channel covariance matrix (C-CCM) estimation method for RIS-aided multiple-input multiple-output systems operating over spatial- and frequency-wideband (dual-wideband) channels. A beam-squint-aware (BSA) orthogonal matching pursuit (OMP) algorithm is proposed to estimate key channel parameters, including angles of arrival (AoAs) at the base station, propagation delays, cascaded angles, and multipath component powers. The estimated parameters are subsequently utilized to construct the C-CCM. Simulation results show that the proposed BSA-OMP method outperforms state-of-the-art approaches in terms of normalized mean square error, spectral efficiency, and outage capacity.

Cite this article as: H. Özen and G. M. Güvensen, “Beam-squint-aware parametric cascaded channel covariance estimation for reconfigurable intelligent surface–aided dual-wideband multiple-input multiple-output,” Electrica, 2026, 26, 0203, doi: 10.5152/electrica.2026.25203.