Mending barrier gaps via mobile sensor nodes with adjustable sensing ranges

Barrier coverage is an important topic in wireless sensor networks. When sensors are randomly deployed, barrier gaps may occur if the number of deployed sensors is not large enough or some sensors start malfunctioning or run out of energy. How to efficiently mend these barrier gaps is an important research issue. In this paper, we study the gap mending problem in a hybrid sensor network which consists of both stationary and mobile sensors with adjustable sensing ranges. We propose two gap mending schemes: the min-max scheme and the max-Iifetime scheme. The first is to minimize the maximal energy consumption to move sensors, and the second is to maximize the lifetime of barrier coverage after mending all gaps. Simulation results show that the min-max scheme can achieve a lower maximal moving distance and the max-Iifetime scheme can efficiently extend the barrier lifetime.