Channel Estimation for Beyond Diagonal RIS-Aided Multi-User mmWave Systems

Fuente: arXiv
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Main Authors: Peng, Linyu, Qiu, Tian, Pan, Cunhua, Wang, Jiangzhou, Zhang, Taihao, Ren, Hong
Format: Preprint
Published: 2026
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author Peng, Linyu
Qiu, Tian
Pan, Cunhua
Wang, Jiangzhou
Zhang, Taihao
Ren, Hong
author_facet Peng, Linyu
Qiu, Tian
Pan, Cunhua
Wang, Jiangzhou
Zhang, Taihao
Ren, Hong
contents Beyond diagonal reconfigurable intelligent surface (BD-RIS) represents a promising architecture for advancing millimeter-wave (mmWave) communications. However, its intricate inter-element connections invalidate the conventional decoupled mathematical structure, thereby severely complicating cascaded channel estimation. In this paper, we formulate a novel block-Kronecker-structured cascaded channel model for a \textit{group-connected} BD-RIS-aided multi-user (MU) mmWave system equipped with uniform planar arrays (UPAs). By exploiting the cascaded channel sparsity, an efficient three-stage estimation protocol is proposed. Specifically, Stage I acquires the common angles of arrival (AoAs) at the base station (BS) via a discrete Fourier transform (DFT)-based approach. Stage II leverages the block-Kronecker structure alongside orthogonal matching pursuit (OMP) and correlation-based least squares (LS) to extract the complete cascaded channel for a designated typical user. Finally, Stage III utilizes a Hierarchical Block OMP (HBOMP) algorithm to estimate the other users' channels. This structurally reconstructs the common and user-specific components, which fundamentally reduces the computational complexity and substantially reduces the pilot overhead. Numerical simulations verify that the proposed protocol yields improved channel estimation accuracy while maintaining a relatively low pilot overhead.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19790
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Channel Estimation for Beyond Diagonal RIS-Aided Multi-User mmWave Systems
Peng, Linyu
Qiu, Tian
Pan, Cunhua
Wang, Jiangzhou
Zhang, Taihao
Ren, Hong
Signal Processing
Beyond diagonal reconfigurable intelligent surface (BD-RIS) represents a promising architecture for advancing millimeter-wave (mmWave) communications. However, its intricate inter-element connections invalidate the conventional decoupled mathematical structure, thereby severely complicating cascaded channel estimation. In this paper, we formulate a novel block-Kronecker-structured cascaded channel model for a \textit{group-connected} BD-RIS-aided multi-user (MU) mmWave system equipped with uniform planar arrays (UPAs). By exploiting the cascaded channel sparsity, an efficient three-stage estimation protocol is proposed. Specifically, Stage I acquires the common angles of arrival (AoAs) at the base station (BS) via a discrete Fourier transform (DFT)-based approach. Stage II leverages the block-Kronecker structure alongside orthogonal matching pursuit (OMP) and correlation-based least squares (LS) to extract the complete cascaded channel for a designated typical user. Finally, Stage III utilizes a Hierarchical Block OMP (HBOMP) algorithm to estimate the other users' channels. This structurally reconstructs the common and user-specific components, which fundamentally reduces the computational complexity and substantially reduces the pilot overhead. Numerical simulations verify that the proposed protocol yields improved channel estimation accuracy while maintaining a relatively low pilot overhead.
title Channel Estimation for Beyond Diagonal RIS-Aided Multi-User mmWave Systems
topic Signal Processing
url https://arxiv.org/abs/2605.19790