Reconfigurable Holographic Surface for Simultaneous Wireless Information and Power Transfer

RESUMO

In this paper, we propose to use a novel reconfigurable holographic surface (RHS) to improve the performance of simultaneous wireless information and power transfer (SWIPT) by exploiting the additional spatial degrees of freedom (DoFs) enabled by the holographic interference principle. Specifically, we study an RHS-empowered SWIPT system in which the digital beamformer at the base station (BS) and the holographic beamformer at the RHS are jointly optimized to maximize the weighted sum-rate of information-decoding (ID) users while guaranteeing a minimum harvested energy requirement for each energy-harvesting (EH) user. Due to the non-convexity of the optimization problem, the weighted sum-rate maximization problem is challenging to solve. We first adopt the weighted minimum mean squared error (WMMSE) method to transform the objective into a more tractable form. We then develop an iterative optimization framework, where the BS digital beamforming and the RHS holographic beamforming subproblems are solved via the majorization-minimization (MM) method. Since solving each subproblem can incur prohibitive complexity as the variable dimension increases, we further propose low-complexity solutions for the two subproblems based on the alternating direction method of multipliers (ADMM) methodology. Numerical results validate the convergence behavior of the proposed algorithms and demonstrate that the RHS-aided BS achieves significant performance gains over a conventional fully-digital BS benchmark. Moreover, the proposed low-complexity algorithms substantially reduce computational complexity while maintaining nearly the same performance.