The charger positioning problem in clustered RF-power harvesting wireless sensor networks

Wireless charging brings forward several new challenges in designing energy efficient wireless sensor networks. In a wireless charging scenario, a number of chargers with high energy resources are placed in the network to recharge power constrained nodes. Nevertheless, due to the fading effect of the signals, a few only nodes can remarkably benefit from the charger power emission. For this reason we examine whether the organization of the nodes in clusters may extend the network lifetime. In this paper, we compute the maximum size of the cluster and we propose an efficient localized algorithm as well as a centralized one to compute the charger position so as to maximize the cluster lifetime. We compare to other solutions in the literature and we present both theoretical and simulation results to show the effectiveness of our approach. The results show an up to 360% increase in lifetime in comparison with the traditional 1-hop communication method between the nodes and the sink.