A Localized Algorithm for Target Monitoring in Wireless Sensor Networks

We consider the following target monitoring problem: Given a set of stationary targets T = {t 1 , *** ,t m } and a set V = {v 1 , *** ,v n } of sensors, the target monitoring problem asks for generating a family of subsets of sensors V 1 , *** ,V s called the monitoring sets , such that each V i monitors all targets. In doing so, the objective of this problem is to maximize z = s /k , where k =max$_{v_j\in V}|\{i:v_j\in V_i\}|$. Maximizing z has direct impact in prolonging the lifetime of sensor networks. For this problem, we present a simple localized algorithm which requires each node to know only its 2-hop neighborhood. Nodes do not need to know their geographic positions. It is shown that the algorithm achieves an optimum result in special cases. We prove that the size of a monitoring set is at most a constant times the size of a minimum monitoring set when the number of targets is a constant. We present extensive simulation results to evaluate the performance of the algorithm.