Low complexity joint beamforming and power splitting for massive MIMO multicasting SWIPT

This paper considers simultaneous wireless information and power transfer in massive multiple-input multiple-output (MIMO) multicasting systems where the base station (BS) is equipped with a very large number of antennas and each mobile station (MS) can receive both information and energy from the signal sent by the BS simultaneously via a power splitting (PS) device, whereby the received signal is split such that a portion of the signal power is fed to the information decoder and the remaining portion of the power to the energy harvester of the receiver. We propose a joint multicast transmit beamforming and receive PS scheme for minimizing the transmit power of the BS subject to signal-to-noise ratio and energy harvesting constraints at each MS. Due to the asymptotic orthogonality of the channel vectors when the number of transmit antennas is large, we are able to obtain the closed-form asymptotically optimal beamforming vector and PS parameters. Therefore the proposed scheme enjoys relatively low computational complexity. Both scenarios of perfect and imperfect channel state information at BS are evaluated. Simulation results verify the effectiveness of the proposed scheme.