Joint transceiver design for simultaneous wireless information and power transfer in multi-user MIMO interference networks

In this paper, we investigate the simultaneous wireless information and power transfer (SWIPT) in multi-user multiple-input multiple-output (MIMO) interference networks. In this system, each transmitter sends one data stream to its targeted receiver through beamforming, while each receiver divides the received signal into two signal flows via power splitting (PS), for information decoding (ID) and energy harvesting (EH), respectively. Different from the existing work in [1], each receiver is equipped with multiple receive antennas, and leverages a receive filter to recover information symbols. Our objective is thus to minimize the total transmit power of all transmitters by jointly designing beamformers, power splitters and receive filters, subject to the signal-to-interference-plus-noise ratio (SINR) constraint for ID and the harvested power constraint for EH at each receiver. To solve this non-convex joint transceiver design problem, an efficient alternating optimization algorithm is proposed via iteratively solving its two convex sub-problems. We prove that the first subproblem relaxed by semidefinite relaxation (SDR) always has a rank-one solution, which indicates the relaxation is actually tight. Numerical results show that the proposed algorithm can save more total transmit power than the existing scheme [1], and its convergence speed is also desirable.