Abstract: A joint hybrid beamforming and power splitting (JHBPS) design problem for simultaneous wireless information and power transfer (SWIPT) in millimeter-wave (mmWave) system is studied. The considered scenario is a multi-antenna base station (BS) transfers information and energy simultaneously to multiple single-antenna receivers. BS adopts hybrid digital and analog beamforming architecture to reduce hardware costs. Receivers separate acquired signals with power splitters either for information decoding (ID) or energy harvesting (EH). The aim is minimizing total transmission power by joint design of hybrid beamforming and PS under ID and EH requirements. It is difficult to obtain the optimal hybrid beamformer directly since the analog beamformer and digital beamformer are
multiplied. Therefore, a two-stage algorithm is proposed to solve the problem. In the first stage, the optimal beamformer and PS ratios are obtained by solving the joint transmission beamforming and PS design problem. In the second stage, the optimal beamformer is approximated with the product of analog beamformer and digital beamformer. The superiority of proposed algorithm over the existing algorithms is demonstrated through simulations. Moreover, the effectiveness of approximation algorithm is testified.

Key words: SWIPT, mmWave, hybrid analog and digital beamforming