Verification of Fresnel Zone Clearance for Line-of-sight Determination in 5.9 GHz Vehicle-to-Vehicle Communications

The determination of the path clearance is one of the most important factors for channel propagation models because most of them classify their models into line-of-sight (LOS) and non-LOS (NLOS) environments. In particular, the path for vehicle-to-vehicle (V2V) communication is more easily obstructed owing to its characteristics such as low antenna heights and high mobility. In this paper, we verify the first Fresnel zone clearance, which is a widely employed method for the determination of path clearance in V2V scenarios. In the analytical model of the first Fresnel zone in V2V scenarios, the ground acts as an obstacle and thus induces NLOS environments for farther than a certain distance. In contrast, our measurement results reveal no additional loss due to the ground obstruction. Therefore, we conclude that the first Fresnel zone calculation is not applicable for determining the path clearance in V2V scenarios, which has significant impact on the accuracy of channel propagation modeling.