Multi-user Downlink with Reconfigurable Intelligent Metasurface Antennas (RIMSA) Array

Fuente: arXiv
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Main Authors: Wei, Xuejian, Wang, Hui-Ming
Format: Preprint
Published: 2025
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author Wei, Xuejian
Wang, Hui-Ming
author_facet Wei, Xuejian
Wang, Hui-Ming
contents Reconfigurable Intelligent Surfaces (RIS) is a transformative technology with great potential in many applications in wireless communications and realizing the Internet of Everything at sixth generation (6G). In this study, we propose a wireless system where the RIS acts as an antenna, which we call Reconfigurable Intelligent Metasurface Antennas (RIMSA). In particular, the base station (BS) equipped with a RIMSA array performs downlink transmissions to multiple users, where each user has a single or multiple RIMSA/RF links, and we aim to solve the sum-rate maximization problem by jointly optimizing the digital processing matrix of the transceivers and the phase responses of RIMSA array at both BS and users. For the multi-user multiple-input single-output (MU-MISO) scenario, we develop an alternating optimization algorithm to slove the problem, where a fractional programming (FP) is used to optimize the digital processing matrix and a product manifold optimization (PMO) is proposed to provide the optimal phase responses of the RIMSA array at both BS and users. For the multi-user multiple-input multiple-output (MU-MIMO) scenario, we equate it to a weighted sum of mean square errors minimization problem, which can be solved by three subproblems iteratively. Both the optimal digital precoder subproblem and the optimal digital combiner subproblem have closed-form solutions, and the subproblem of RIMSA configuration is solved by the PMO algorithm as well. Simulation results demonstrate that the proposed algorithms achieve significant performance gains over conventional algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2506_18418
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-user Downlink with Reconfigurable Intelligent Metasurface Antennas (RIMSA) Array
Wei, Xuejian
Wang, Hui-Ming
Information Theory
Signal Processing
Reconfigurable Intelligent Surfaces (RIS) is a transformative technology with great potential in many applications in wireless communications and realizing the Internet of Everything at sixth generation (6G). In this study, we propose a wireless system where the RIS acts as an antenna, which we call Reconfigurable Intelligent Metasurface Antennas (RIMSA). In particular, the base station (BS) equipped with a RIMSA array performs downlink transmissions to multiple users, where each user has a single or multiple RIMSA/RF links, and we aim to solve the sum-rate maximization problem by jointly optimizing the digital processing matrix of the transceivers and the phase responses of RIMSA array at both BS and users. For the multi-user multiple-input single-output (MU-MISO) scenario, we develop an alternating optimization algorithm to slove the problem, where a fractional programming (FP) is used to optimize the digital processing matrix and a product manifold optimization (PMO) is proposed to provide the optimal phase responses of the RIMSA array at both BS and users. For the multi-user multiple-input multiple-output (MU-MIMO) scenario, we equate it to a weighted sum of mean square errors minimization problem, which can be solved by three subproblems iteratively. Both the optimal digital precoder subproblem and the optimal digital combiner subproblem have closed-form solutions, and the subproblem of RIMSA configuration is solved by the PMO algorithm as well. Simulation results demonstrate that the proposed algorithms achieve significant performance gains over conventional algorithms.
title Multi-user Downlink with Reconfigurable Intelligent Metasurface Antennas (RIMSA) Array
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2506.18418