Near-field Spatial-domain Channel Extrapolation for XL-MIMO Systems

Fuente: arXiv
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Main Authors: Lu, Jiayi, Zhang, Jiayi, Lei, Hao, Xiao, Huahua, Ai, Bo, Ng, Derrick Wing Kwan
Format: Preprint
Published: 2025
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author Lu, Jiayi
Zhang, Jiayi
Lei, Hao
Xiao, Huahua
Ai, Bo
Ng, Derrick Wing Kwan
author_facet Lu, Jiayi
Zhang, Jiayi
Lei, Hao
Xiao, Huahua
Ai, Bo
Ng, Derrick Wing Kwan
contents Extremely large-scale multiple-input multiple-output (XL-MIMO) systems are pivotal to next-generation wireless communications, where dynamic RF chain architectures offer enhanced performance. However, efficient precoding in such systems requires accurate channel state information (CSI) obtained with low complexity. To address this challenge, spatial-domain channel extrapolation has attracted growing interest. Existing methods often overlook near-field spherical wavefronts or rely heavily on sparsity priors, leading to performance degradation. In this paper, we propose an adaptive near-field channel extrapolation framework for multi-subcarrier XL-MIMO systems, leveraging a strategically selected subset of antennas. Subsequently, we develop both on-grid and off-grid algorithms, where the latter refines the former's estimates for improved accuracy. To further reduce complexity, a cross-validation (CV)-based scheme is introduced. Additionally, we analytically formulate the mutual coherence of the sensing matrix and propose a coherence-minimizing-based random pattern to ensure robust extrapolation. Numerical results validate that the proposed algorithms significantly outperform existing methods in both extrapolation accuracy and achievable rate, while maintaining low computational complexity. In particular, our proposed CV ratio offers a flexible trade-off between accuracy and efficiency, and the corresponding off-grid algorithm achieves high accuracy with complexity comparable to conventional on-grid methods.
format Preprint
id arxiv_https___arxiv_org_abs_2509_20026
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Near-field Spatial-domain Channel Extrapolation for XL-MIMO Systems
Lu, Jiayi
Zhang, Jiayi
Lei, Hao
Xiao, Huahua
Ai, Bo
Ng, Derrick Wing Kwan
Signal Processing
Extremely large-scale multiple-input multiple-output (XL-MIMO) systems are pivotal to next-generation wireless communications, where dynamic RF chain architectures offer enhanced performance. However, efficient precoding in such systems requires accurate channel state information (CSI) obtained with low complexity. To address this challenge, spatial-domain channel extrapolation has attracted growing interest. Existing methods often overlook near-field spherical wavefronts or rely heavily on sparsity priors, leading to performance degradation. In this paper, we propose an adaptive near-field channel extrapolation framework for multi-subcarrier XL-MIMO systems, leveraging a strategically selected subset of antennas. Subsequently, we develop both on-grid and off-grid algorithms, where the latter refines the former's estimates for improved accuracy. To further reduce complexity, a cross-validation (CV)-based scheme is introduced. Additionally, we analytically formulate the mutual coherence of the sensing matrix and propose a coherence-minimizing-based random pattern to ensure robust extrapolation. Numerical results validate that the proposed algorithms significantly outperform existing methods in both extrapolation accuracy and achievable rate, while maintaining low computational complexity. In particular, our proposed CV ratio offers a flexible trade-off between accuracy and efficiency, and the corresponding off-grid algorithm achieves high accuracy with complexity comparable to conventional on-grid methods.
title Near-field Spatial-domain Channel Extrapolation for XL-MIMO Systems
topic Signal Processing
url https://arxiv.org/abs/2509.20026