Channel Estimation for Holographic Communications in Hybrid Near-Far Field

Fuente: arXiv
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Auteurs principaux: Yue, Shaohua, Zeng, Shuhao, Liu, Liang, Di, Boya
Format: Preprint
Publié: 2024
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author Yue, Shaohua
Zeng, Shuhao
Liu, Liang
Di, Boya
author_facet Yue, Shaohua
Zeng, Shuhao
Liu, Liang
Di, Boya
contents To realize holographic communications, a potential technology for spectrum efficiency improvement in the future sixth-generation (6G) network, antenna arrays inlaid with numerous antenna elements will be deployed. However, the increase in antenna aperture size makes some users lie in the Fresnel region, leading to the hybrid near-field and far-field communication mode, where the conventional far-field channel estimation methods no longer work well. To tackle the above challenge, this paper considers channel estimation in a hybrid-field multipath environment, where each user and each scatterer can be in either the far-field or the near-field region. First, a joint angular-polar domain channel transform is designed to capture the hybrid-field channel's near-field and far-field features. We then analyze the power diffusion effect in the hybrid-field channel, which indicates that the power corresponding to one near-field (far-field) path component of the multipath channel may spread to far-field (near-field) paths and causes estimation error. We design a novel power-diffusion-based orthogonal matching pursuit channel estimation algorithm (PD-OMP). It can eliminate the prior knowledge requirement of path numbers in the far field and near field, which is a must in other OMP-based channel estimation algorithms. Simulation results show that PD-OMP outperforms current hybrid-field channel estimation methods.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08149
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Channel Estimation for Holographic Communications in Hybrid Near-Far Field
Yue, Shaohua
Zeng, Shuhao
Liu, Liang
Di, Boya
Information Theory
Signal Processing
To realize holographic communications, a potential technology for spectrum efficiency improvement in the future sixth-generation (6G) network, antenna arrays inlaid with numerous antenna elements will be deployed. However, the increase in antenna aperture size makes some users lie in the Fresnel region, leading to the hybrid near-field and far-field communication mode, where the conventional far-field channel estimation methods no longer work well. To tackle the above challenge, this paper considers channel estimation in a hybrid-field multipath environment, where each user and each scatterer can be in either the far-field or the near-field region. First, a joint angular-polar domain channel transform is designed to capture the hybrid-field channel's near-field and far-field features. We then analyze the power diffusion effect in the hybrid-field channel, which indicates that the power corresponding to one near-field (far-field) path component of the multipath channel may spread to far-field (near-field) paths and causes estimation error. We design a novel power-diffusion-based orthogonal matching pursuit channel estimation algorithm (PD-OMP). It can eliminate the prior knowledge requirement of path numbers in the far field and near field, which is a must in other OMP-based channel estimation algorithms. Simulation results show that PD-OMP outperforms current hybrid-field channel estimation methods.
title Channel Estimation for Holographic Communications in Hybrid Near-Far Field
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2401.08149