Weighted Sum Rate Maximization for Two-Way Wireless Powered Interference Channels

Interference is a detrimental factor for information decoding, but it can be a helpful resource for energy harvesting in a wireless powered network. Considering a two-way wireless powered interference channel, in this study, we present a simultaneous wireless information and power transfer (SWIPT)-then-wireless information transfer (WIT) protocol. In this protocol, transmitters perform SWIPT, and receivers receive both information and energy simultaneously in the forward link (FL). Then, the receivers perform WIT using the harvested energy in the backward link (BL). To maximize the weighted sum rate of the FL and BL, we jointly optimize the transmit power and energy harvesting (EH) ratio according to time switching and power splitting policies. To solve this non-convex optimization problem, we propose an iterative power control and energy harvesting algorithm based on dual methods that reduce computational complexity. The results show that the proposed algorithm finds the optimal transmit power and EH ratio suitably and thus maximizes the weighted sum rate. Consequently, the proposed SWIPT-then-WIT protocol expands the achievable rate region significantly compared with conventional schemes that do not adaptively control the transmit power and EH ratio.