Efficient and robust serial query processing approach for large-scale wireless sensor networks

The goal of query processing in WSN is to get reliable information of interest from sensor nodes whilst preserving, as much as possible, the network resources, mainly energy: Among the various approaches proposed in the literature to tackle this issue, serial approaches, in which the query is carried out serially from node to node, have shown noticeable improvements in terms of query processing responsiveness and communication overhead reduction when compared to centralized and distributed ones. Nevertheless, they suffer two main drawbacks: (a) they are intrinsically very vulnerable and (b) they require the construction of a Hamiltonian path through the network, which is known to be a NP-Complete problem. In this paper, we investigate the issue of efficient and robust query processing by proposing a novel approach, which we refer to as GBT (Greedy & Boundary Traversal). GBT is of a serialized and localized nature (i.e., each node does not maintain any knowledge about the topology of the network). Furthermore, in GBT the selection of the next hop is totally independent from the previous hops (i.e., no path is defined in advance). This feature enforces the robustness of GBT as attested by the simulation results we obtained (a mean improvement of almost 50% reduction in terms of communication, energy and query responsiveness in large-scale network topologies). We also provide a complexity analysis (time, space and communication) of our query processing algorithm as well as formal proof of its correctness (i.e., termination and completeness). (C) 2016 Elsevier B.V. All rights reserved.