Reconfigurable intelligent surface (RIS)-based communication networks promise to improve channel capacity and energy efficiency. However, the promised capacity gains could be negligible for passive RISs because of the double pathloss effect. Active RISs can overcome this issue because they have reflector elements with a low-cost amplifier. This letter studies the active RIS-aided simultaneous wireless information and power transfer (SWIPT) in a multiuser system. The users exploit power splitting (PS) to decode information and harvest energy simultaneously based on a realistic piecewise nonlinear energy harvesting model. The goal is to minimize the base station (BS) transmit power by optimizing its beamformers, PS ratios, and RIS phase shifts/amplification factors. The simulation results show significant improvements (e.g., 19% and 28%) with the maximum reflect power of 10 mW and 15 mW, respectively, compared to the passive RIS without higher computational complexity cost. We also show the robustness of the proposed algorithm against imperfect channel state information.
@article{arxiv.2206.14326,
title = {Multiuser MISO PS-SWIPT Systems: Active or Passive RIS?},
author = {Shayan Zargari and Azar Hakimi and Chintha Tellambura and Sanjeewa Herath},
journal= {arXiv preprint arXiv:2206.14326},
year = {2022}
}
Comments
Accepted for publication in the IEEE Wireless Communications Letters