Connected coverage in WSNs based on critical targets

One of the recent challenges in wireless sensor networks is the design of efficient algorithms to monitor a set of discrete targets lying at a field. A set of active nodes must cover all the available targets and at the same time retain connectivity with the sink. Such a set can remain active until one active node depletes its battery. In this paper, we analyze the problem of finding the proper sensor scheduling in order to maximize the total network lifetime. We present OCCH (optimized connected coverage heuristic) an efficient algorithm that is based on a general connected coverage methodology. This methodology takes into account the association of the sensors with the poorly covered targets that set an upper bound on the overall computed lifetime. Two solutions are presented to efficiently manage the battery life of these sensors followed by other minor improvements that prolong the network lifetime. Extensive simulation results are presented that show that our solution outperforms other known algorithms found in the literature in terms of achievable network lifetime.