Partially Controlled Deployment Strategies for Wireless Sensors

In this paper we study the following problem: we are given a certain one- ortwo-dimensional region R to monitor and a requirement on the degree of coverage (DoC) of R to meet by a network of deployed sensors. The latter will be dropped by a moving vehicle, which can release sensors at arbitrary points within R. The node spatial distribution when sensors are dropped at a certain point is modeled by a certain probability density function F. The network designer is allowed to choose an arbitrary set of drop points, and to release an arbitrary number of sensors at each point. Given this setting, we consider the problem of determining the best performing strategy among a certain set of grid-like strategies that reflect the (one- or two-dimensional) symmetry of the region to be monitored. The best performing deployment strategy is such that (1) the DoC requirement is fulfilled and (2) the total number of deployed nodes n is minimum. We study this problem both analytically and through simulation, under the assumption that F is the two-dimensional Normal distribution centered at the drop point.The main contribution of this paper is an in-depth study of the inter-relationships between environmental conditions, DoC requirement, and cost of the deployment.