Near-Ground Channel Modeling for Distributed Cooperative Communications

Abstract

A computationally efficient near-ground field prediction model is proposed to facilitate realistic wireless sensor network (WSN) simulations. In this model, using the principle of Fresnel zones, path loss is split into three segments. Certain propagation mechanisms dominate in each part. The distances that define the edges of each section are derived theoretically. The model is validated against several experimental datasets obtained in open and forested areas. It is noticed that the proposed model has higher accuracy compared to existing analytical near-ground propagation models. This enhancement is achieved by careful assessment of key features relevant to near-grazing propagation such as diffraction loss due to obstruction of the first Fresnel zone and higher order waves produced by terrain irregularities. Monte Carlo simulations are used to investigate the effects of antenna height, frequency of operation, polarization, and terrain dielectric and roughness properties on WSNs performance. It is realized that antenna height is by far the most influential geometric parameter to low-altitude WSNs connectivity and average number of neighbors.