Maximizing Lifetime and Handling Reliability in Wireless Sensor Networks Using Adjustable Sensing Ranges

Wireless sensor networks are generally characterized by a large number of small sensing devices (sensors), randomly disposed all over the region of interest in order to perform a monitoring activity on a set of target points. To maximize the total coverage time during which all the target are simultaneously monitored (i.e., the network lifetime) sensors can be opportunely scheduled by switching them between on and off mode so that the limited battery power is efficiently used. In this paper, we propose a methodology to prevent sensor failure that results in a shortage of network lifetime only when a sensor effectively fails. Indeed, when a sensor fails, the monitoring radii of the other sensors in the cover can be opportunely enlarged to maintain coverage of the entire set of targets. In this way, each target can be ‘potentially’ k-covered, but network lifetime would be affected only if a sensor effectively fails. In this paper we address the problem of maximizing network lifetime by potentially ensuring k-coverage of the targets by means of adjustable sensing radii. Our preliminary analysis and results will be presented.