Propagation model for high altitude platform systems based on ray tracing simulation

Satellites and HAPS can be used as a platform to extend connectivity to remote areas and bring about 5G services to under-served populations. We have conducted ray tracing simulations to study signal propagation from HAPS to ground using maps of Chicago downtown and a suburban residential area. Using the ray tracing data, we developed a simple path loss model to estimate the propagation loss in a combination of free space propagation and terrestrial clutter induced attenuation. The model can be characterized by two environment specific parameters and is applicable to arbitrary vehicle height and elevation angle. We also present in this paper multipath characteristics in suburban and dense urban environments that are useful for fast fading modeling and system design.