Resource allocation in wireless powered relay networks through a nash bargaining game

Simultaneously information and power transfer in mobile relay networks have recently emerged, where relays can harvest the radio frequency (RF) energy and then use this energy for data forwarding and system operation. However, most of the previous works do not consider that relays may have their own objectives, such as harvesting more residual energy for maximizing its own data transmission instead of reaching a single goal of the network. Therefore, in this paper, we propose a Nash bargaining approach to balance the information transmission efficiency of source-to-destination pairs and the residual harvested energy of relays. We theoretically analyze and prove that this Nash bargaining problem has several desirable properties such as the quasi-concavity when it is decomposed into three sub-problems: energy harvesting power optimization, time division between information transmission and energy harvesting, and the power control for information transmission. Based on the theoretical analysis, we propose an alternating power control and time division scheme to find a sub-optimal solution. Simulation results clearly show and demonstrate the properties of the problem and the convergence of our algorithm.