Analysis on Energy Efficiency of RIS-Assisted Multiuser Downlink Near-Field Communications

Fuente: arXiv
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Auteurs principaux: Wang, Wei, Ou, Xiaoyu, Ren, Zhihan, Abbas, Waqas Bin, Dang, Shuping, Doufexi, Angela, Beach, Mark A.
Format: Preprint
Publié: 2025
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author Wang, Wei
Ou, Xiaoyu
Ren, Zhihan
Abbas, Waqas Bin
Dang, Shuping
Doufexi, Angela
Beach, Mark A.
author_facet Wang, Wei
Ou, Xiaoyu
Ren, Zhihan
Abbas, Waqas Bin
Dang, Shuping
Doufexi, Angela
Beach, Mark A.
contents In this paper, we focus on the energy efficiency (EE) optimization and analysis of reconfigurable intelligent surface (RIS)-assisted multiuser downlink near-field communications. Specifically, we conduct a comprehensive study on several key factors affecting EE performance, including the number of RIS elements, the types of reconfigurable elements, reconfiguration resolutions, and the maximum transmit power. To accurately capture the power characteristics of RISs, we adopt more practical power consumption models for three commonly used reconfigurable elements in RISs: PIN diodes, varactor diodes, and radio frequency (RF) switches. These different elements may result in RIS systems exhibiting significantly different energy efficiencies (EEs), even when their spectral efficiencies (SEs) are similar. Considering discrete phases implemented at most RISs in practice, which makes their optimization NP-hard, we develop a nested alternating optimization framework to maximize EE, consisting of an outer integer-based optimization for discrete RIS phase reconfigurations and a nested non-convex optimization for continuous transmit power allocation within each iteration. Extensive comparisons with multiple benchmark schemes validate the effectiveness and efficiency of the proposed framework. Furthermore, based on the proposed optimization method, we analyze the EE performance of RISs across different key factors and identify the optimal RIS architecture yielding the highest EE.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18076
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analysis on Energy Efficiency of RIS-Assisted Multiuser Downlink Near-Field Communications
Wang, Wei
Ou, Xiaoyu
Ren, Zhihan
Abbas, Waqas Bin
Dang, Shuping
Doufexi, Angela
Beach, Mark A.
Signal Processing
Systems and Control
In this paper, we focus on the energy efficiency (EE) optimization and analysis of reconfigurable intelligent surface (RIS)-assisted multiuser downlink near-field communications. Specifically, we conduct a comprehensive study on several key factors affecting EE performance, including the number of RIS elements, the types of reconfigurable elements, reconfiguration resolutions, and the maximum transmit power. To accurately capture the power characteristics of RISs, we adopt more practical power consumption models for three commonly used reconfigurable elements in RISs: PIN diodes, varactor diodes, and radio frequency (RF) switches. These different elements may result in RIS systems exhibiting significantly different energy efficiencies (EEs), even when their spectral efficiencies (SEs) are similar. Considering discrete phases implemented at most RISs in practice, which makes their optimization NP-hard, we develop a nested alternating optimization framework to maximize EE, consisting of an outer integer-based optimization for discrete RIS phase reconfigurations and a nested non-convex optimization for continuous transmit power allocation within each iteration. Extensive comparisons with multiple benchmark schemes validate the effectiveness and efficiency of the proposed framework. Furthermore, based on the proposed optimization method, we analyze the EE performance of RISs across different key factors and identify the optimal RIS architecture yielding the highest EE.
title Analysis on Energy Efficiency of RIS-Assisted Multiuser Downlink Near-Field Communications
topic Signal Processing
Systems and Control
url https://arxiv.org/abs/2505.18076