Energy-efficient aggregate query evaluation in sensor networks

Sensor networks, consisting of sensor devices equipped with energy-limited batteries, have been widely used for surveillance and monitoring environments. Data collected by the sensor devices needs to be extracted and aggregated for a wide variety of purposes. Due to the serious energy constraint imposed on such a network, it is a great challenge to perform aggregate queries efficiently. This paper considers the aggregate query evaluation in a sensor network database with the objective to prolong the network lifetime. We first propose an algorithm by introducing a node capability concept that balances the residual energy and the energy consumption at each node so that the network lifetime is prolonged. We then present an improved algorithm to reduce the total network energy consumption for a query by allowing group aggregation. We finally evaluate the performance of the two proposed algorithms against the existing algorithms through simulations. The experimental results show that the proposed algorithms outperform the existing algorithms significantly in terms of the network lifetime.