Multiuser MISO PS-SWIPT Systems: Active or Passive RIS?

Reconfigurable intelligent surface (RIS)-based communication networks promise to improve channel capacity and energy efficiency. However, the promised gains could be negligible for passive RISs because of double pathloss effect. Active can overcome this issue they have reflector elements with a low-cost amplifier. This letter studies active RIS-aided simultaneous wireless information power transfer (SWIPT) in multiuser system. The users exploit splitting (PS) decode harvest simultaneously based on realistic piecewise nonlinear harvesting model. goal is minimize base station (BS) transmit by optimizing its beamformers, PS ratios, RIS phase shifts/amplification factors. simulation results show significant improvements (e.g., 19% 28%) maximum reflect 10 mW 15 mW, respectively, compared without higher computational complexity cost. We also robustness proposed algorithm against imperfect state information.