Power allocation for three-phase two-way relay networks with simultaneous wireless information and power transfer

This paper considers a three-phase two-way relay system in which two single-antenna transceivers exchange data with the help of a multi-antenna energy harvesting relay. An SNR maximization problem is formulated under fixed total power and fairness constraints. Given the fraction of energy harvested by the relay in the first two phases, a closed-form expression for the optimal power allocation between the transceivers is derived. Simulation results show that three-phase two-way relaying can have better performance than conventional two-phase two-way relaying, especially if the number of antennas at the relay is large.