Spatial query processing in wireless sensor networks – A survey

Wireless sensor networks (WSN) are particularly useful for obtaining data concerning events limited to a well-defined geographic region, such as a disaster site or a malfunctioning subsection of a factory plant. Such applications typically use spatial queries, which are SQL-like queries where location constraints are imposed on the collected data. Further, spatial queries allow changing the set of nodes (the region of interest) at runtime. This work surveys spatial queries in WSN. Due to the particular energy and resource constraints of WSN, spatial queries are performed by mechanisms having several stages, each of them implemented using localized distributed algorithms. This article categorizes the existing strategies for each stage, in order to ease the understanding of the state of the art. Finally, we analyze the most recent works on spatial query processing, identifying which classes of algorithms are used on each stage.