Approximation Algorithms for Road Coverage Using Wireless Sensor Networks for Moving Objects Monitoring

Coverage problem in wireless sensor networks measures how well a region or parts of it is sensed by the deployed sensors. Definition of coverage metric depends on its applications for which sensors are deployed. In this paper, we introduce a new quality control metric/measure called road coverage. It will be used for measuring efficiency of a sensor network, which is deployed for tracking moving/mobile objects in a road network. A road segment is a sub-part of a road network. A road segment is said to be road covered if an object travels through the entire road segment then it must be detected somewhere on the road segment by a sensor. First, we propose different definitions of road coverage metrics. Thereafter, algorithms are proposed to measure those proposed road coverage metrics. It is shown that the problem of deploying minimum number of sensors to road cover a set of road segments is NP-hard. Constant factor approximation algorithms are proposed for road covering axis-parallel road segments. Experimental performance analysis of our algorithms are evaluated through simulations.