A load-balanced cross-layer design for energy-harvesting sensor networks

Abstract

To extend the lifetime of the individual nodes in a wireless sensor network (WSN), energy conservation has been a prominent design goal. Among the most popular energy optimization schemes is the pursuance of a hierarchical topology, e.g., forming clusters, and energy aware routing. Recent advances in the area of energy harvesting from ambient sources have enabled the development of rechargeable devices that can be leveraged in developing a long-lasting WSN. Furthermore, since nodes may be scavenging energy at a varying rate, energy transfer over radio frequency (RF) links has been adopted as a means for the network to perpetually remain operational. Thus, an energy-harvesting WSN (EHWSN) introduces new challenges and warrants unconventional management strategies. In this paper, we propose a novel CRoss-layer design for WSNs with Energy Scavenging and Transfer capabilities (CREST). CREST is a distributed approach that forms a two-tier routing topology by grouping nodes into clusters. The network is divided into virtual tracks, whose width is based on proximity to the base-station (BS) and node density. The rate of energy gain from the environment and from other nodes is the criterion for selecting a cluster-head (CH). The cluster size is determined in order to even the load among all CHs while observing that the traffic load increases when getting closer to the BS. Finally, the sensor data are disseminated to the BS over inter-CH paths determined by a novel energy-transferring-based routing algorithm. The performance of CREST is validated through analysis and simulation.