Response time constrained top-k query evaluation in sensor networks

Existing solutions for top-k queries in wireless sensor networks mainly focused on energy efficiency and little attention has been paid to the response time to answer a top-k query as well as the relationship between the response time and the network lifetime. In this paper we address this issue explicitly by studying the top-k query problem in sensor networks with the response time constraint. We aim at finding an energy-efficient routing tree and devising an evaluation algorithm for top-k queries on the tree such that the network lifetime is significantly prolonged, provided that the query response time constraint is met too. To do so, we propose a novel joint optimization framework of finding a routing tree and devising a filter-based evaluation algorithm on the tree. We also conduct extensive experiments by simulation to evaluate the performance of the proposed algorithms. The experimental results showed that the joint optimization framework prolongs the network lifetime significantly under a given response time constraint.