Critical sensor density for fault-tolerant coverage in 3D heterogeneous wireless sensor networks

Coverage is an important metric used to measure the quality of service of three-dimensional wireless sensor networks (3D WSNs) monitoring a field of interest (FoI). While it is important to ensure the desired level of coverage, it is also necessary to do so with a minimum number of sensors from a network cost perspective. In this paper, we assume that the sensors are deployed at random uniformly in a three-dimensional FoI and all the sensors may not have the same sensing range and/or probability of being alive. In such a 3D heterogeneous WSN, we derive the critical condition for the desired level of coverage of the FoI using a probabilistic model. We validate our analysis and demonstrate its benefits. We also demonstrate an application of the analysis to the design of a minimum-cost 3D heterogeneous WSN.