Energy-efficient coverage using sensors with continuously adjustable sensing ranges

This paper investigates the target coverage problem in wireless sensor networks with continuously adjustable sensing range. We study a wireless sensor network consisting a large number of N sensors that are randomly deployed over an area of interest and are expected to cover a number of M targets for a period of time as long as possible. For each sensor, the operation of sensing may consume energy which varies with different sensing ranges for which it may operate. Since targets are redundantly covered by multiple sensors, to conserve energy resources, sensors can be organized into a number of non-disjoint sets and activate them set by set. We define the maximal lifetime with constrained energy (MLCE) problem that has its objective of finding the operation time to each set of sensors such that the total operation time is maximized. Since the MLCE problem is NP-complete, two greedy heuristics is designed for solving this problem.