Optimization of IRS-assisted OFDMA SWIPT Systems with Dynamic Subcarrier Allocation and AC Computing

This study aims to explore the potential of an intelligent reflecting surface (IRS) in facilitating simultaneous wireless information and power transfer (SWIPT) in an orthogonal frequency division multiple access (OFDMA) system. A power-splitting (PS) protocol is employed to enable both energy harvesting (EH) and information decoding (ID). Moreover, an alternating current computing (ACC) is integrated into the EH receivers to directly utilize the harvested AC power, unlike the conventional direct current computing (DCC) approach. Specifically, we consider joint optimization of beamforming, dynamic subcarrier allocation (SA), IRS phase shift, PS coefficient, and ACC coefficient for the IRS-assisted OFDMA-SWIFT system, with the objective of maximizing the overall sum rate. To solve the optimization problem, we propose an alternating optimization (AO) framework combined with inner approximation (IA) methods. Numerical results demonstrate the effectiveness of the proposed system, as compared to alternative approaches.