Enhancing Energy Harvesting Efficiency for IRS-Aided TS-SWIPT Network with Practical Phase Shifts

Recently, intelligent reflecting surface (IRS) emerges as a promising technique to improve the spectral and energy efficiency in communication with low cost and low energy consumption. In this work, we investigate the simultaneous wireless information and power transfer (SWIPT) network with time-switching (TS) receivers where the base station (BS) sends both information and energy signals to the users with the aid of IRS. The phase shifts at the IRS elements are appropriately adjusted to enhance the transmission performance in terms of energy and information efficiency. The energy harvesting efficiency, i.e., the ratio of the sum harvested energy at the users and the transmission power at the BS is maximized while the required information rate at the users is guaranteed, the transmission power is limited, and the practical phase shifts are constrained. The iterative algorithm with the non-convex approximations is proposed to achieve the information beamformers, energy covariance matrix, and TS ratios. Lastly, the numerical simulations present the convergence and effectiveness of the proposed approach.