N-Ray Ground Interference: Extending the Two-Ray Interference Model for 3D Terrain Shapes

The two-ray path loss model is a well-known model in wireless communications and has also found wide-spread use in vehicular network simulation. However, its applicability in three-dimensional scenarios is questionable as it assumes a planar ground surface between sender and receiver. In contrast, a terrain shape of varying inclination can lead to an arbitrary number of reflected rays, which cannot be handled by the two-ray model. Therefore, we present the derivation and impementation of an n-ray ground interference model to estimate the corresponding path loss. Using the new model, two sample scenarios are analyzed to compare the path loss resulting from 2-ray and n-ray ground interference. The results indicate considerable differences, emphasizing the need for the n-ray ground interference model in three-dimensional V2X scenarios.