Beamformer Design in RIS-Assisted Multi-Carrier SWIPT System with Sub-THz Transmission

Abstract

This work presents a low-complexity algorithm for minimizing the total transmit power in a reconfigurable intelligent surface (RIS)-assisted simultaneous wireless information and power transfer network. Towards this, a power minimization problem is formulated subject to information communication and energy harvesting constraints, by jointly optimizing base station and RIS beamformers with power splitting ratios of energy-harvesting communication users. For reducing the computational complexity, the proposed algorithm first solves an approximate power minimization problem to find an appropriate initial point, which is then used for further optimization through iterative successive convex approximation (SCA)-based algorithm. The simulation results demonstrate that the proposed algorithm achieves significant reduction in computational complexity, in terms of the number of iterations needed to achieve convergence, without compromising on performance.