Weighted Codebook Scheme for RIS-Assisted Point-to-Point MIMO Communications

Fuente: arXiv
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Main Authors: Yu, Zhiheng, An, Jiancheng, Gan, Lu, Li, Hongbin, Chatzinotas, Symeon
Format: Preprint
Published: 2025
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author Yu, Zhiheng
An, Jiancheng
Gan, Lu
Li, Hongbin
Chatzinotas, Symeon
author_facet Yu, Zhiheng
An, Jiancheng
Gan, Lu
Li, Hongbin
Chatzinotas, Symeon
contents Reconfigurable intelligent surfaces (RIS) can reshape the characteristics of wireless channels by intelligently regulating the phase shifts of reflecting elements. Recently, various codebook schemes have been utilized to optimize the reflection coefficients (RCs); however, the selection of the optimal codeword is usually obtained by evaluating a metric of interest. In this letter, we propose a novel weighted design on the discrete Fourier transform (DFT) codebook to obtain the optimal RCs for RIS-assisted point-to-point multiple-input multiple-output (MIMO) systems. Specifically, we first introduce a channel training protocol where we configure the RIS RCs using the DFT codebook to obtain a set of observations through the uplink training process. Secondly, based on these observed samples, the Lagrange multiplier method is utilized to optimize the weights in an iterative manner, which could result in a higher channel capacity for assisting in the downlink data transmission. Thirdly, we investigate the effect of different codeword configuration orders on system performance and design an efficient codeword configuration method based on statistical channel state information (CSI). Finally, numerical simulations are provided to demonstrate the performance of the proposed scheme.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06944
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Weighted Codebook Scheme for RIS-Assisted Point-to-Point MIMO Communications
Yu, Zhiheng
An, Jiancheng
Gan, Lu
Li, Hongbin
Chatzinotas, Symeon
Information Theory
Signal Processing
Reconfigurable intelligent surfaces (RIS) can reshape the characteristics of wireless channels by intelligently regulating the phase shifts of reflecting elements. Recently, various codebook schemes have been utilized to optimize the reflection coefficients (RCs); however, the selection of the optimal codeword is usually obtained by evaluating a metric of interest. In this letter, we propose a novel weighted design on the discrete Fourier transform (DFT) codebook to obtain the optimal RCs for RIS-assisted point-to-point multiple-input multiple-output (MIMO) systems. Specifically, we first introduce a channel training protocol where we configure the RIS RCs using the DFT codebook to obtain a set of observations through the uplink training process. Secondly, based on these observed samples, the Lagrange multiplier method is utilized to optimize the weights in an iterative manner, which could result in a higher channel capacity for assisting in the downlink data transmission. Thirdly, we investigate the effect of different codeword configuration orders on system performance and design an efficient codeword configuration method based on statistical channel state information (CSI). Finally, numerical simulations are provided to demonstrate the performance of the proposed scheme.
title Weighted Codebook Scheme for RIS-Assisted Point-to-Point MIMO Communications
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2503.06944