JBRC: Jointly Balanced Routing and Charging Scheme for RF Energy Harvesting Wireless Sensor Networks

In radio frequency (RF) energy harvesting wireless sensor networks, employing a mobile charger (MC) is more cost-efficient and flexible to power the sensor nodes than deploying extensive stationary chargers. However, due to limited charging time of MC, the nodes' residual energy distribution (i.e., energy balance degree) after charging will directly determine the lifetime of sensor networks. To promote the energy balance degree, two important problems required to solve are: how to determine the nodes' routing scheme and how to schedule the MC to power the nodes. The two problems interact with each other. In this paper, we introduce a practical charging scenario, consider to combine the routing-based charging and charging-based routing, and propose a Jointly Balanced Routing and Charging (JBRC) scheme. Specifically, we propose a balanced routing strategy and a charging time allocation scheme, and iteratively jointly optimize them. Our goal is to achieve the energy balance in WSNs, i.e., maximizing the minimal residual energy among nodes. Additionally, the MC's moving trajectory is selected and designed. From simulation experiments, we verify the superiority of our proposed JBRC scheme.