Joint Beamforming Design for STAR-RIS-Aided MU-MIMO System with SWIPT

This paper investigates the resource allocation problem in a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided simultaneous wireless information and power transfer (SWIPT) system. Specifically, the considered system is motivated by the smart interference management of STAR-RIS with extended coverage capability and energy-efficient communication for the information receivers and intelligent power transfer to energy receivers present in private industry networks. We focus on the problem of power minimization for the STAR-aided SWIPT system via a joint beamforming design at the BS and STAR-RIS while guaranteeing the minimum QoS for SWIPT. To solve the formulated problem, we first transform the problem into a simplified form and later propose an alternating optimization framework to solve the problems of beamforming design at BS and STAR-RIS independently and iteratively. Simulation results confirm that STAR-RIS can significantly reduce the required transmission power approximately by 15-20% when compared to conventional RIS while satisfying given QoS constraints for SWIPT systems.