Opportunistic Routing in Large-Scale Energy Harvesting Sensor Networks

Abstract

Large-scale wireless sensor networks (WSNs) suffer from the serious problem of lack of energy self- sufficiency. Indeed, providing sensors with adequate energy over long periods is a major bottleneck in the implementation of WSNs. In this regard, energy harvesting (EH), i.e., continuously capturing energy from ambient renewable sources, is a promising solution for low-power and low data-rate WSNs. The drawback is that the energy available to a sensor is random and this randomness forces the redesign of WSNs protocols. Our specific interest here is to enable the delivery of sensed data to a fusion center (FC) in a large-scale EH WSN. We propose a novel, energy- aware, opportunistic routing protocol in a large- scale EH WSN requiring multi-hop communication. In choosing the best forwarding partner, our proposed protocol considers the remaining energy at sensor nodes, their distances from the FC and the amount of data to be transmitted; importantly, we make no assumptions on prior knowledge of the network topology. As our numerical results show, the proposed protocol significantly increases the data delivery ratio as compared to the state-of-the- art. Our second contribution is to introduce an EH-aware manner for distributing sensors in the environment such that all nodes have approximately equal number of data transmissions independent of their locations.