Feasibility Study Regarding Self-Sustainable Reconfigurable Intelligent Surfaces

2026-01-08

IEEE Wireless Communications Letters

AI Summary

This study investigates the deployment feasibility of self-sustaining reconfigurable intelligent surfaces (ssRISs)—which operate without external power—in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, with a focus on the co-design challenges between energy harvesting and signal reflection. By systematically comparing element-switching (ES) and time-switching (TS) harvest-and-reflect (HaR) mechanisms through stochastic geometry and link-level modeling, the work jointly optimizes energy harvesting efficiency and phase-shift configuration. The analysis reveals that TS benefits from channel hardening in stable environments, offering hardware-efficient solutions suitable for reliable low-to-moderate-rate communications, whereas ES demonstrates superior scalability and robustness under poor energy harvesting conditions, requiring only a linear increase in the number of elements. These findings provide theoretical foundations and practical guidelines for ssRIS deployment strategies.

Technology Category

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Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Responsible Web: Social and technical mechanisms of refusal for web technologies and applications

Abstract

Without requiring operational costs such as cabling and powering while maintaining reconfigurable phase-shift capability, self-sustainable reconfigurable intelligent surfaces (ssRISs) can be deployed in locations inaccessible to conventional relays or base stations, offering a novel approach to enhance wireless coverage. This letter assesses the feasibility of ssRIS deployment by analyzing two harvest-and-reflect (HaR) schemes: element-splitting (ES) and time-splitting (TS). We examine how element requirements scale with key system parameters, transmit power, data rate demands, and outage constraints under both line-of-sight (LOS) and non-line-of-sight (NLOS) ssRIS-to-user equipment (UE) channels. Analytical and numerical results reveal distinct feasibility characteristics. The TS scheme demonstrates better channel hardening gain, maintaining stable element requirements across varying outage margins, making it advantageous for indoor deployments with favorable harvesting conditions and moderate data rates. However, TS exhibits an element requirement that exponentially scales to harvesting difficulty and data rate. Conversely, the ES scheme shows only linear growth with harvesting difficulty, providing better feasibility under challenging outdoor scenarios. These findings establish that TS excels in benign environments, prioritizing reliability, while ES is preferable for demanding conditions requiring operational robustness.

Problem

• self-sustainable reconfigurable intelligent surfaces
• harvest-and-reflect
• feasibility study
• wireless coverage
• outage constraints

Innovation

• self-sustainable RIS
• harvest-and-reflect
• element-splitting
• time-splitting
• channel hardening