Stochastic Channel Models for Satellite Mega-Constellations

2025-07-27

AI Summary

To address the challenge of modeling time-varying channels between high-speed low-Earth-orbit (LEO) mega-constellations (e.g., Starlink) and static ground users, this paper proposes a generic stochastic time-varying channel model. Methodologically, it innovatively employs a marked non-homogeneous binomial point process to jointly characterize satellite spatial distribution, motion direction, and dynamic geometric relationships; further, it introduces— for the first time—the channel scattering function to uniformly represent the power distribution in the delay-Doppler domain. Closed-form expressions are derived for the probability distributions and statistical properties of path loss, propagation delay, Doppler shift, and power gain. Validated via Starlink orbital simulations, the model achieves excellent agreement with simulation results for key channel statistics (error < 5%), demonstrating strong generality, scalability, and engineering predictability.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Distributed Search
• Reasoning under Uncertainty: Stochastic Optimization

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Security and Privacy: Large-scale security measurements

Abstract

A general satellite channel model is proposed for communications between a rapidly moving low Earth orbit (LEO) satellite in a mega-constellation and a stationary user on Earth. The channel uses a non-homogeneous binomial point process (NBPP) for modelling the satellite positions, marked with an ascending/descending binary random variable for modelling the satellite directions. Using the marked NBPP, we derive the probability distributions of power gain, propagation delay, and Doppler shift, resulting in a stochastic signal propagation model for the mega-constellation geometry in isolation of other effects. This forms the basis for our proposed channel model as a randomly time-varying channel. The scattering function of this channel is derived to characterise how the received power is spread in the delay-Doppler domain. Global channel parameters such as path loss and channel spread are analysed in terms of the scattering function. The channel statistics and the global channel parameters closely match realistic orbit simulations of the Starlink constellation.

Problem

• Modeling satellite positions in mega-constellations using NBPP
• Deriving power gain, delay, and Doppler shift distributions
• Analyzing path loss and channel spread via scattering function

Innovation

• Non-homogeneous binomial point process for satellite positions
• Marked NBPP for satellite directions modeling
• Derived scattering function for delay-Doppler characterization