Beamforming Design with Partial Channel Estimation and Feedback for FDD RIS-Assisted Systems

Fuente: arXiv
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Autores principales: Ge, Xiaochun, Yu, Shanping, Shen, Wenqian, Xing, Chengwen, Shim, Byonghyo
Formato: Preprint
Publicado: 2023
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author Ge, Xiaochun
Yu, Shanping
Shen, Wenqian
Xing, Chengwen
Shim, Byonghyo
author_facet Ge, Xiaochun
Yu, Shanping
Shen, Wenqian
Xing, Chengwen
Shim, Byonghyo
contents Beamforming design with partial channel estimation and feedback for frequency-division duplexing (FDD) reconfigurable intelligent surface (RIS) assisted systems is considered in this paper. We leverage the observation that path angle information (PAI) varies more slowly than path gain information (PGI). Then, several dominant paths are selected among all the cascaded paths according to the known PAI for maximizing the spectral efficiency of downlink data transmission. To acquire the dominating path gain information (DPGI, also regarded as the path gains of selected dominant paths) at the base station (BS), we propose a DPGI estimation and feedback scheme by jointly beamforming design at BS and RIS. Both the required number of downlink pilot signals and the length of uplink feedback vector are reduced to the number of dominant paths, and thus we achieve a great reduction of the pilot overhead and feedback overhead. Furthermore, we optimize the active BS beamformer and passive RIS beamformer by exploiting the feedback DPGI to further improve the spectral efficiency. From numerical results, we demonstrate the superiority of our proposed algorithms over the conventional schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2302_11997
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Beamforming Design with Partial Channel Estimation and Feedback for FDD RIS-Assisted Systems
Ge, Xiaochun
Yu, Shanping
Shen, Wenqian
Xing, Chengwen
Shim, Byonghyo
Signal Processing
Beamforming design with partial channel estimation and feedback for frequency-division duplexing (FDD) reconfigurable intelligent surface (RIS) assisted systems is considered in this paper. We leverage the observation that path angle information (PAI) varies more slowly than path gain information (PGI). Then, several dominant paths are selected among all the cascaded paths according to the known PAI for maximizing the spectral efficiency of downlink data transmission. To acquire the dominating path gain information (DPGI, also regarded as the path gains of selected dominant paths) at the base station (BS), we propose a DPGI estimation and feedback scheme by jointly beamforming design at BS and RIS. Both the required number of downlink pilot signals and the length of uplink feedback vector are reduced to the number of dominant paths, and thus we achieve a great reduction of the pilot overhead and feedback overhead. Furthermore, we optimize the active BS beamformer and passive RIS beamformer by exploiting the feedback DPGI to further improve the spectral efficiency. From numerical results, we demonstrate the superiority of our proposed algorithms over the conventional schemes.
title Beamforming Design with Partial Channel Estimation and Feedback for FDD RIS-Assisted Systems
topic Signal Processing
url https://arxiv.org/abs/2302.11997