Energy-Efficient Multiple Query Optimization for Wireless Sensor Networks

A wireless sensor network is a collection of sensor nodes distributed over a geographic area to monitor physical conditions, such as temperature, light, humidity, or pressure. Since a sensor node has limited energy supply, running multiple continuous monitoring queries may impose significant overhead on the sensor network. In this paper, we propose an energy-efficient multiple query optimization method to reduce the number of monitoring queries that are running in the sensor network. When a new monitoring query is submitted to the base station, the proposed method checks whether the new query can be evaluated using results of currently running queries. If so, the proposed method rewrites the new query using currently running queries and then evaluates the rewritten query at the base station without injecting it into the sensor network. Consequently, the amount of data transmitted from sensor nodes to the base station is reduced, resulting in lower energy consumption.Through experiments,we show the effectiveness of the proposed method.