Propagation Loss Measurements and Two Slope Modelling in Vehicular Environments for Intelligent Transportation Systems

Radio Frequency (RF) propagation in vehicular environments exhibits major transformations from indoor, outdoor and farmland multipath environments. The innovative advancement in Wireless Sensor Networks (WSNs) has made it necessary to recognise and predict the RF propagation losses for WSNs in vehicular environments. Very few models exist for network planning and deployment in vehicular environments. All of these models need an extensive statistical estimations and an in-depth knowledge of the vehicular environment. In this paper a different approach has been pursued and as a first step is to evaluate the factors which affect RF propagation in vehicular environments and how these factors affect each other while predicting propagation losses in vehicular environments. Existing research contributions has been consolidated and a two slope model which has been considered more appropriate for vehicular environments is proposed by performing Path Loss (PL) measurements in a Sports Utility Vehicle (SUV) at 915 MHz and 2400 MHz employing Vector Signal Analyzer / Vector Signal Generator and compared with Matlab simulations. Based on the results of frequent measurements and modelling, the proposed two slope model is observed to be applicable for deployment and prediction of PL in Line-of-Sight (LoS) scenarios at very low antenna heights in vehicular environments at short-range.