Optimal Operation of Active RIS-Aided Wireless Powered Communications in IoT Networks

TL;DR

This paper investigates the use of active reconfigurable intelligent surfaces (RIS) to improve wireless-powered communication in IoT networks, deriving formulas and optimizing parameters to enhance energy transfer and data rates.

Contribution

It introduces the application of active RIS in WPC-enabled IoT networks, providing novel analytical expressions and optimization strategies for system performance.

Findings

Active RIS significantly improves ergodic rate and reduces outage probability.

Optimized parameters enhance energy transfer and communication efficiency.

Active RIS outperforms passive RIS in WPC scenarios.

Abstract

Wireless-powered communications (WPCs) are increasingly crucial for extending the lifespan of low-power Internet of Things (IoT) devices. Furthermore, reconfigurable intelligent surfaces (RISs) can create favorable electromagnetic environments by providing alternative signal paths to counteract blockages. The strategic integration of WPC and RIS technologies can significantly enhance energy transfer and data transmission efficiency. However, passive RISs suffer from double-fading attenuation over RIS-aided cascaded links. In this article, we propose the application of an active RIS within WPC-enabled IoT networks. The enhanced flexibility of the active RIS in terms of energy transfer and information transmission is investigated using adjustable parameters. We derive novel closed-form expressions for the ergodic rate and outage probability by incorporating key parameters, including signal amplification, active noise, power consumption, and phase quantization errors. Additionally, we explore the optimization of WPC scenarios, focusing on the time-switching factor and power consumption of the active RIS. The results validate our analysis, demonstrating that an active RIS significantly enhances WPC performance compared to a passive RIS.