Top-k Queries in Wireless Sensor Networks Leveraging Hierarchical Grid Index

In the Internet of Things, smart things communicate with each other, and sensed data are aggregated and queried for satisfying certain requests of end-users. Wireless sensor networks (WSN) is a key enabling technique for achieving the vision of the Internet of Things. In real applications of WSN, such as environmental monitoring and vehicle tracking, they may require to launch spatial queries for collecting sensory data to achieve certain goals. Among various queries, top-k query is one of the fundamental operators in many applications of wireless sensor networks for phenomenon monitoring. In this paper we propose a novel top-k query algorithm based on hierarchical grid index and range filter of head nodes, which is able to filter out as many unlikely top-k results as early as possible within the network from transmission.