Joint Beamforming with Extremely Large Scale RIS: A Sequential Multi-Agent A2C Approach

Fuente: arXiv
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Auteurs principaux: Chai, Zhi, Xu, Jiajie, Coon, Justin P, Alouini, Mohamed-Slim
Format: Preprint
Publié: 2025
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author Chai, Zhi
Xu, Jiajie
Coon, Justin P
Alouini, Mohamed-Slim
author_facet Chai, Zhi
Xu, Jiajie
Coon, Justin P
Alouini, Mohamed-Slim
contents It is a challenging problem to jointly optimize the base station (BS) precoding matrix and the reconfigurable intelligent surface (RIS) phases simultaneously in a RIS-assisted multiple-user multiple-input-multiple-output (MU-MIMO) scenario when the size of the RIS becomes extremely large. In this paper, we propose a deep reinforcement learning algorithm called sequential multi-agent advantage actor-critic (A2C) to solve this problem. In addition, the discrete phase of RISs, imperfect channel state information (CSI), and channel correlations between users are taken into consideration. The computational complexity is also analyzed, and the performance of the proposed algorithm is compared with the zero-forcing (ZF) beamformer in terms of the sum spectral efficiency (SE). It is noted that the computational complexity of the proposed algorithm is lower than the benchmark, while the performance is better than the benchmark. Throughout simulations, it is also found that the proposed algorithm is robust to medium channel estimation error.
format Preprint
id arxiv_https___arxiv_org_abs_2506_10815
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Joint Beamforming with Extremely Large Scale RIS: A Sequential Multi-Agent A2C Approach
Chai, Zhi
Xu, Jiajie
Coon, Justin P
Alouini, Mohamed-Slim
Systems and Control
It is a challenging problem to jointly optimize the base station (BS) precoding matrix and the reconfigurable intelligent surface (RIS) phases simultaneously in a RIS-assisted multiple-user multiple-input-multiple-output (MU-MIMO) scenario when the size of the RIS becomes extremely large. In this paper, we propose a deep reinforcement learning algorithm called sequential multi-agent advantage actor-critic (A2C) to solve this problem. In addition, the discrete phase of RISs, imperfect channel state information (CSI), and channel correlations between users are taken into consideration. The computational complexity is also analyzed, and the performance of the proposed algorithm is compared with the zero-forcing (ZF) beamformer in terms of the sum spectral efficiency (SE). It is noted that the computational complexity of the proposed algorithm is lower than the benchmark, while the performance is better than the benchmark. Throughout simulations, it is also found that the proposed algorithm is robust to medium channel estimation error.
title Joint Beamforming with Extremely Large Scale RIS: A Sequential Multi-Agent A2C Approach
topic Systems and Control
url https://arxiv.org/abs/2506.10815