Near-Field Channel Estimation for mmWave/THz Communications with Extremely Large-Scale UPAs

Fuente: arXiv
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Main Authors: Chen, Yiming, Wang, Hongwei, Li, Lingxiang, Chen, Zhi
Format: Preprint
Published: 2026
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author Chen, Yiming
Wang, Hongwei
Li, Lingxiang
Chen, Zhi
author_facet Chen, Yiming
Wang, Hongwei
Li, Lingxiang
Chen, Zhi
contents Extremely large antenna arrays (ELAAs) are widely adopted in mmWave/THz communications to compensate for the severe path loss, wherein the channel estimation remains a significant challenge since the Rayleigh distance of ELAAs stretches to tens or even hundreds of meters and the near-field channel model should be considered. Existing polar-domain based methods and block-sparse based methods are originally devised for Uniform Linear Arrays (ULAs) near-field channel estimation. The polar-domain based method can be applied to Uniform Planar Arrays (UPAs), but it behaves plain since it ignores the specific sparsity structure of the UPA near-field channels. Meanwhile, the block-sparse based method cannot be extended to the UPA scenarios directly. To address these issues, we first reformulate the original UPA near-field channel as an outer product of two ULA near-field channels and we construct a modified two-dimensional DFT (2D-DFT) dictionary for it. With the proposed dictionary, we further prove that the UPA near-field channel admits a 2D block-sparse structure. Leveraging this specific sparse structure, we solve the channel estimation problem with the 2D Pattern-Coupled Sparse Bayesian Learning (2D-PCSBL) algorithm. Simulation results show that the proposed approach outperforms conventional existing methods while maintaining a comparable computational complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14437
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Near-Field Channel Estimation for mmWave/THz Communications with Extremely Large-Scale UPAs
Chen, Yiming
Wang, Hongwei
Li, Lingxiang
Chen, Zhi
Signal Processing
Extremely large antenna arrays (ELAAs) are widely adopted in mmWave/THz communications to compensate for the severe path loss, wherein the channel estimation remains a significant challenge since the Rayleigh distance of ELAAs stretches to tens or even hundreds of meters and the near-field channel model should be considered. Existing polar-domain based methods and block-sparse based methods are originally devised for Uniform Linear Arrays (ULAs) near-field channel estimation. The polar-domain based method can be applied to Uniform Planar Arrays (UPAs), but it behaves plain since it ignores the specific sparsity structure of the UPA near-field channels. Meanwhile, the block-sparse based method cannot be extended to the UPA scenarios directly. To address these issues, we first reformulate the original UPA near-field channel as an outer product of two ULA near-field channels and we construct a modified two-dimensional DFT (2D-DFT) dictionary for it. With the proposed dictionary, we further prove that the UPA near-field channel admits a 2D block-sparse structure. Leveraging this specific sparse structure, we solve the channel estimation problem with the 2D Pattern-Coupled Sparse Bayesian Learning (2D-PCSBL) algorithm. Simulation results show that the proposed approach outperforms conventional existing methods while maintaining a comparable computational complexity.
title Near-Field Channel Estimation for mmWave/THz Communications with Extremely Large-Scale UPAs
topic Signal Processing
url https://arxiv.org/abs/2603.14437