Reconfigurable Intelligent Surface-Aided Near-field Communications for 6G: Opportunities and Challenges

Fuente: arXiv
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Main Authors: Mu, Xidong, Xu, Jiaqi, Liu, Yuanwei, Hanzo, Lajos
Format: Preprint
Published: 2023
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author Mu, Xidong
Xu, Jiaqi
Liu, Yuanwei
Hanzo, Lajos
author_facet Mu, Xidong
Xu, Jiaqi
Liu, Yuanwei
Hanzo, Lajos
contents Reconfigurable intelligent surface (RIS)-aided near-field communications is investigated. First, the necessity of investigating RIS-aided near-field communications and the advantages brought about by the unique spherical-wave-based near-field propagation are discussed. Then, the family of patch-array-based RISs and metasurface-based RISs are introduced along with their respective near-field channel models. A pair of fundamental performance limits of RIS-aided near-field communications, namely their power scaling law and effective degrees-of-freedom, are analyzed for both patch-array-based and metasurface-based RISs, which reveals the potential performance gains that can be achieved. Furthermore, the associated near-field beam training and beamforming design issues are studied, where a two-stage hierarchical beam training approach and a low-complexity element-wise beamforming design are proposed for RIS-aided near-field communications. Finally, a suite of open research problems is highlighted for motivating future research.
format Preprint
id arxiv_https___arxiv_org_abs_2312_13004
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Reconfigurable Intelligent Surface-Aided Near-field Communications for 6G: Opportunities and Challenges
Mu, Xidong
Xu, Jiaqi
Liu, Yuanwei
Hanzo, Lajos
Information Theory
Signal Processing
Reconfigurable intelligent surface (RIS)-aided near-field communications is investigated. First, the necessity of investigating RIS-aided near-field communications and the advantages brought about by the unique spherical-wave-based near-field propagation are discussed. Then, the family of patch-array-based RISs and metasurface-based RISs are introduced along with their respective near-field channel models. A pair of fundamental performance limits of RIS-aided near-field communications, namely their power scaling law and effective degrees-of-freedom, are analyzed for both patch-array-based and metasurface-based RISs, which reveals the potential performance gains that can be achieved. Furthermore, the associated near-field beam training and beamforming design issues are studied, where a two-stage hierarchical beam training approach and a low-complexity element-wise beamforming design are proposed for RIS-aided near-field communications. Finally, a suite of open research problems is highlighted for motivating future research.
title Reconfigurable Intelligent Surface-Aided Near-field Communications for 6G: Opportunities and Challenges
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2312.13004