A survey on in-network querying and tracking services for wireless sensor networks

In wireless sensor networks, querying services purpose to detect static events while tracking services continuously monitor mobile events. This paper surveys and discusses in-network querying and tracking services for static and mobile networks. Querying and tracking services are categorized by tree-based, hierarchical cluster-based, geometrical and hash-based. Mobility effects of network units and several design metrics including energy-efficiency, distance-sensitivity, scalability and fault-tolerance are also discussed. The paper includes open research issues for querying and tracking services in various domains.