Energy Correlation in Wirelessly Powered Networks

Abstract

This paper investigates the spatial correlation of the energy harvested from a Poisson field of RF power sources. Specifically, we focus on two energy harvesting models—one dependent on distance alone and the other with more practical factors taken into account—with the aim of showing how the actual point process of nodes that successfully harvest energy looks visually and characterize the pair correlation functions for such point process under the two models theoretically. It turns out that for both models the resulting process of the energized nodes exhibits positive correlations. Therefore, we further approximate the point process formed by active RF-powered nodes with a fitted Poisson cluster process, which is shown to provide a good approximation of the success probability in the information transmission. An important conclusion is that though the Poisson point process has been widely used to model the spatial configuration of energized nodes, it is inadequate for modeling the locations of the active RF-powered nodes due to the positive correlation.