Geometry-Based Stochastic Probability Models for the LoS and NLoS Paths of A2G Channels under Urban Scenario

TL;DR

This paper introduces three novel stochastic probability models for LoS, GS, and BS paths in urban A2G channels, accounting for 3D scattering environments, altitudes, and Fresnel zone effects, validated by simulations and ray-tracing.

Contribution

The paper presents new geometric stochastic models for A2G path probabilities in urban scenarios, considering detailed environmental and altitude factors.

Findings

Models perform well across different frequencies and altitudes.

Models align with existing models at extreme altitudes.

Good agreement with ray-tracing simulations.

Abstract

Path probability prediction is essential to describe the dynamic birth and death of propagation paths, and build the accurate channel model for air-to-ground (A2G) communications. The occurrence probability of each path is complex and time-variant due to fast changeable altitudes of UAVs and scattering environments. Considering the A2G channels under urban scenarios, this paper presents three novel stochastic probability models for the line-of-sight (LoS) path, ground specular (GS) path, and building-scattering (BS) path, respectively. By analyzing the geometric stochastic information of three-dimensional (3D) scattering environments, the proposed models are derived with respect to the width, height, and distribution of buildings. The effect of Fresnel zone and altitudes of transceivers are also taken into account. Simulation results show that the proposed LoS path probability model has good performance at different frequencies and altitudes, and is also consistent with existing models at the low or high altitude. Moreover, the proposed LoS and NLoS path probability models show good agreement with the ray-tracing (RT) simulation method.