RIS-assisted OFDM-based SWIPT System

Abstract

Reconfigurable Intelligent Surfaces (RIS) and Simultaneous Wireless Information and Power Transfer (SWIPT) are prominently emerging technologies in the field of wireless communications. RIS enhances signal strength and coverage by intelligently adjusting the phase shifts of electromagnetic waves, while SWIPT enables the concurrent transmission of information and power, addressing the growing demand for energy-efficient networks. In this paper, we explored resource allocation algorithms for RIS assisted SWIPT system, utilizing Orthogonal Frequency-Division Multiplexing (OFDM) for data transmission. The system consists of a single RIS that aids communication between a base station (BS) and the user equipment (UE). Each RIS element reflects multiple orthogonal sub-carriers, optimizing the overall system performance. Two novel algorithms for OFDM sub-carrier allocation and RIS element selection are proposed such that the data rate and the harvested energy are maximized at the user end, where the separated architecture of the SWIPT technology is employed. Numerical results confers that increasing number of RIS elements and OFDM sub-carriers enhances both the data rate and the energy harvested, underscoring the effectiveness of our optimization approach. © 2025 IEEE.