A Ray-Based Characterization of Satellite-to-Urban Propagation

TL;DR

This paper uses ray-tracing simulations to analyze satellite-to-urban ground propagation, focusing on key channel parameters like Rician K-factor and delay spread across different urban layouts and use cases.

Contribution

It provides a detailed characterization of satellite-to-urban propagation mechanisms and their dependence on urban morphology and satellite elevation, aiding future channel modeling.

Findings

Channel dispersion varies significantly with satellite elevation.

Urban morphology strongly influences fading characteristics.

Different use cases exhibit distinct propagation behaviors.

Abstract

The evolution toward 6G communication systems is expected to rely on integrated three-dimensional network architectures where terrestrial infrastructures coexist with non-terrestrial stations such as satellites, enabling ubiquitous connectivity and service continuity. In this context, accurate channel models for satellite-to-ground propagation in urban environments are essential, particularly for user equipment located at street level where obstruction and multipath effects are significant. This work investigates satellite-to-urban propagation through deterministic ray-tracing simulations. Three representative urban layouts are considered, namely dense urban, urban, and suburban. Multiple use cases are investigated, including handheld devices, vehicular terminals, and fixed rooftop receivers operating across several frequency bands. The analysis focuses on the relative importance of competing propagation mechanisms and on two key channel parameters, namely the Rician K-factor and the delay spread, which are relevant for the calibration of channel models to be used in link- and system-level simulations. Results highlight the strong - and in some cases unconventional - dependence of channel dispersion and fading characteristics on satellite elevation, antenna placement, and urban morphology.