Mobile Energy Balancing in Heterogeneous Opportunistic Networks

Energy is a scarce resource in mobile networks consisting of devices running on batteries. Thus, many studies have looked at the energy management issue in these networks from different aspects. Thanks to the recent advances in wireless power transfer (WPT) technology, the wireless charging of the mobile devices has been considered for their continuous operation. While most of the research efforts have focused on the scheduling of mobile chargers for charging of the devices (e.g., sensor) in the field, interesting research problems such as energy balancing among a population of nodes have also emerged with the consideration of bidirectional wireless charging among nodes. Energy balancing aims to balance the energy among nodes towards prolonging the network lifetime especially when external energy sources are not available. Previous studies target an energy balance among the devices as fast as possible but they waste energy in the network during this process due to the excessive interactions between nodes. Moreover, they do not take into account the heterogeneous contact relations between the nodes in the network. In this paper, we address these issues and present efficient and loss-aware energy balancing protocols considering the contact graph heterogeneity between nodes and a time threshold for completing the energy balancing. Simulation results show that the proposed algorithms outperform the previous work by reaching a better energy balance with a lower energy loss within the restricted relations among nodes in the network.