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.
This research was supported by \\u201CRegional Innovation Strategy (RIS)\\u201D through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2021RIS-004), by the Basic Science Research Program through the NRF funded by the MOE (NRF-2022R1I1A1A01071807, 2021R1I1A3041887), by the Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the government of Korea (Ministry of Science & ICT (MSIT)) (2022-0-00704, Development of 3D-NET Core Technology for High-Mobility Vehicular Service). A.-A. A. Boulogeorgos research was supported by MINOAS project, within the H.F.R.I call \\u201DBasic Research Financing (Horizontal Support of all Sciences)\\u201D under the National Recovery and Resilience Plan \\u201CGreece 2.0\\u201D funded by the European Union - NextGenerationEU (H.F.R.I. Project Number: 15857). (Corresponding authors: Howon Lee and Heejung Yu.) Waqas Khalid is with the Institute of Industrial Technology, Korea University, Sejong 30019, Korea. Email: waqas283@{korea.ac.kr, gmail.com}.
