CRT: Collision-Tolerant Residence Time for Deterministic Transmission in LEO Satellite Networks

2026-05-05

AI Summary

This work addresses the challenge that conventional Time-Sensitive Networking (TSN) mechanisms fail in Low Earth Orbit (LEO) satellite networks due to their highly dynamic topology and the infeasibility of global time synchronization. To overcome this, the paper introduces the CRT framework, which, for the first time, incorporates collision tolerance into deterministic scheduling for LEO satellites. CRT compensates for link delay variations by locally regulating per-hop residence times using local clocks, thereby ensuring end-to-end deterministic transmission without requiring global synchronization. Building on formal modeling, the authors design CRT-Fast, a heuristic algorithm that jointly optimizes schedulability and jitter control through iterative layering and path continuity enhancement. Simulations under high-load scenarios on Iridium and Starlink constellations demonstrate that the proposed approach significantly reduces delay jitter and improves flow schedulability.

Abstract

Low-Earth Orbit (LEO) satellite networks are a key enabler for the 6G Non-Terrestrial Network (NTN) architecture. However, supporting time-sensitive services in LEO networks is challenging due to highly dynamic topologies and the difficulty of maintaining precise global time synchronization. Existing Time-Sensitive Networking (TSN) mechanisms largely rely on static topologies and strict synchronization, which makes them ill-suited to dynamic LEO environments. To address this issue, we propose CRT, a deterministic transmission framework tailored for LEO networks. CRT regulates per-hop residence time using local clocks, thereby compensating for link-delay variations without requiring strict global synchronization. To handle asynchronous collisions, CRT adopts a collision-tolerant scheduling strategy that maximizes the number of schedulable flows while bounding collision-induced jitter. We formalize the corresponding scheduling problem and show that it is NP-hard. We further develop CRT-Fast, an efficient heuristic algorithm. It combines iterative layering with path continuity to control collision intensity and improve path stability under topology changes. Simulations on Iridium and Starlink constellations show that the proposed method achieves lower delay jitter and high schedulability under heavy traffic loads.

Problem

• LEO satellite networks
• Time-Sensitive Networking
• deterministic transmission
• global time synchronization
• dynamic topologies

Innovation

• deterministic transmission
• residence time
• collision-tolerant scheduling
• LEO satellite networks
• time-sensitive networking