Path Loss Results for Wireless Sensor Network Deployment in a Long Grass Environment

In this paper, a full set of radio frequency (RF) propagation measurements is provided for wireless sensor nodes deployed in a long grass environment. The measurements were made to evaluate signal attenuation in open space environments where long grasses are present. Empirical RF models are often derived from such measurements, which for the case of this paper has already been presented in previous work. In this paper, however, more details on model derivation are provided as well as the variations of received signal strength (RSS) for eight different distances. In addition, the empirical path loss model of the investigated environment is compared with models previously presented in other outdoor environments. These environments are sand terrain, concrete terrain, dense tree, sparse tree, and artificial turf. Comparing these different environments together shows major differences in the prediction of path loss values, path loss exponent (PLE), and variation elements. Furthermore, the empirical model is compared with popular theoretical models (i.e., free space path loss and two ray path loss). The comparison results show an inaccuracy of RSS values predicted by these theoretical models for WSN deployment in long grass environments.