Large Network Target Coverage Protocols

Abstract

The problem of energy aware wireless accessibility from a collection of statically positioned sensor nodes to a given set of target nodes is considered. The simple plain-disc-model with the sensing radius ρs of wireless nodes is well known. Constant guarantee approximation algorithm is known for the ideal disk model but we will continue the study of general model in the case with hindrances. This model is defined by the use of matrices of sensor-target accessibility. The traditional connectivity issue of WSN is out of the scope of current research and the focus is on coverage. We aim at applying the widely-decentralized time-sharing model, where sensors collectively share the duty of continuous covering of the total collection of the set of targets. That is, when part of the nodes may accept for a time interval the sleep regime, minimizing in this way the energy consumption. In an easy step we obtain, that the mathematical problems arisen are related to the well-known combinatorial set cover problems. Set cover is one of the typical NP complete problems, which means that our solution will likely be not exact, but – approximate, or even heuristic. We bring analysis of the theoretical resources around these postulations. An extension of Integer Linear Programming model is implemented and demonstrated, being applied on the WSN domain coverage issues. In a complementary manner, and for the first time, we manage the appearing covering structures using the terms of monotone Boolean functions (the main result)