Coverage and Connectivity Preserving Routing Protocol for heterogeneous wireless sensor networks

Coverage preservation and connectivity are the most essential functions to guarantee quality of service (QoS) in wireless sensor network. Therefore, the goal of an optimal sensor deployment strategy is to have a globally connected network, while optimizing coverage at the same time. By optimizing coverage, the deployment strategy would guarantee that optimum area in the sensing field is covered by sensors, as required by various types of mission-critical applications involving extensive battlefield surveillance, medical healthcare, etc. Whereas by ensuring that the network is connected, it is ensured that the sensed information is transmitted to other nodes and possibly to a centralized base station which makes valuable decisions for the applications. However, a tradeoff exists between sensing coverage and network lifetime due to the limited energy supplies of sensor nodes. In this paper, we propose a Coverage and Connectivity Preserving Routing Protocol for heterogeneous wireless sensor networks (CCPRP) to accommodate connectivity, energy-balance and coverage-preservation for sensor nodes in wireless sensor networks that are hierarchically clustered. The energy consumption for radio transmissions and the residual energy over the network are taken into account when the proposed protocol determines an energy-efficient route for a data from elected cluster head to the base station through elected gateway, we define a cost metric that favours those nodes being more energy-redundantly covered as better candidates for cluster heads in a way to improve the performance of sensing coverage, reduce communications energy and prolonging the effective network lifetime with optimal data delivery. The simulation results demonstrate that the proposed protocol is able to increase the duration of the on-duty network and provide up to 108.7% of extra service time with 100% sensing coverage ratio comparing with other existing protocols.