Obstacle-avoidance minimal exposure path for heterogeneous wireless sensor networks

The exploration of the minimal exposure path has significance in guiding the movement of unauthorized objects through monitored areas. In wireless sensor networks, the minimal exposure path can be further used to evaluate the worst-case coverage. This paper analyzes the minimal exposure path in an area that contains heterogeneous sensor nodes and various obstacles. Two exposure-based coverage models are first established to describe the detection patterns of both omnidirectional and directional sensing units. Based on the models, the exposure value of an arbitrary path can be mathematically derived. Next, the obstacle-avoidance minimal exposure path searching (OMEPS) algorithm is proposed to find the minimal exposure path in an environment that includes obstacles. In addition to searching for areas with a poor degree of coverage, OMEPS guides mobile objects through coverage holes caused by obstacles without fear of exposure. Simulation results demonstrate that OMEPS can enable a heterogeneous wireless sensor network to efficiently determine its minimal exposure path. Additional sensors can then be deployed along the minimal exposure path to improve the quality of coverage.