Abstract: Simultaneous wireless information and power transfer (SWIPT) is an effective way to prolong the operation time of energy-constrained wireless relay systems. A large-scale antenna array based SWIPT orthogonal frequency division multiplexing (OFDM) decode and forward (DF) relay system, in which the source is equipped with large-scale antenna array, is considered. The transmission process is divided into three time-slots. In the first time-slot, the source transmits power to the relay using maximum ratio transmission beamforming; in the second time-slot, the source transmits information to the relay; in the third time-slots, the relay transmits the information to the destination using the harvested energy in the first time-slot. Both the power allocation (PA) over the sub-carriers for information and power transmissions from the source to the relay and from the relay to the destination, and the time allocation (TA) between the first, second and third time-slots are investigated. An optimal joint PA and TA algorithm has been proposed. Computer simulation results shows that the proposed algorithm outperforms some benchmark schemes.

Key words: SWIPT, OFDM, large-scale antenna array, decode-and-forward relay, time and power allocation