Social-Aware Energy Balancing in Mobile Opportunistic Networks

Thanks to the recent advances in wireless power transfer technology and its adoption in mobile portable devices (e.g., smartphones), an alternative energy replenishment option for users has emerged through peer-to-peer energy sharing among devices. Such a notion of energy sharing among nodes in a mobile opportunistic network can help balance the energy levels of nodes and can keep them connected, prolonging the lifetime of the network. Existing works studying the energy balancing problem mainly focus on decreasing of the energy difference among nodes as fast as possible, thus consider sharing of the energy among meeting nodes equally. However, in an opportunistic network consisting of mobile devices carried by people (i.e., also called mobile social network), due to the underlying social relations between people, there will be multiple social groups affecting the contact relations between nodes. While nodes in the same group interact more often, the nodes in different groups interact less frequently. Moreover, there is usually a smaller number of nodes from different groups that interact (i.e., bridge nodes), providing limited opportunity for energy transfer between groups. In this study, we look at the energy balancing problem considering the underlying social network structure and present a two-stage social-aware energy balancing protocol for a fast balancing process. To this end, we integrate the roles of nodes (e.g., bridge/non-bridge node) as well as the average energy differences between different groups to determine the amount of energy transfer between meeting nodes. Through simulations, we demonstrate that the proposed social-aware energy balancing protocol performs better than the state-of-the-art.