Coverage preservation in energy harvesting wireless sensor networks for rare events

Wireless sensor networks for rarely occurring geospatial events must minimally maintain constant sensing coverage to ensure detection wherever and whenever such events occur. This paper proposes an Equitable Sleep Coverage Algorithm for Rare Geospatial Occurrences (ESCARGO) for timely event notification where the network must also maintain connectivity at all times regardless of the significant energy cost of doing so. This non time-synchronized, fully distributed duty-cycling algorithm is shown to significantly extend the operational lifetime of battery powered rare event sensing networks with an optimised, low node density, non-random deployment scheme without compromising detection probability or notification delay. The algorithm is further shown to facilitate potentially indefinite coverage maintenance in sensor networks powered by small form factor solar panels without relying on charging efficiencies beyond the capabilities of existing technology.