Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Inter-Satellite Link Configuration for Fast Delivery in Low-Earth-Orbit Constellations

Arman Mollakhani, Jerayu Tiamraj, Shu-Jie Cao, Dongning Guo

TL;DR

This work tackles latency optimization in large LEO satellite constellations by formulating inter-plane ISL selection as a diameter-minimization problem under realistic geometric and hardware constraints. It proposes an iterative local-search algorithm that starts from a baseline topology with two intra-plane links per satellite and up to two inter-plane links, refining inter-plane connections to reduce the network diameter while ensuring long-term link viability. The study analyzes two operational models: a snapshot-only feasibility model and a viability-constrained model that enforces link validity over an orbital period, revealing a clear trade-off between low latency and topology stability. Simulation results show that snapshot-only designs achieve smaller diameters but higher link churn, whereas viability-constrained designs provide robust, deployable topologies with higher worst-case latency, guiding design choices for centralized routing in mega-LEO constellations.

Abstract

End-to-end latency in large low-Earth-orbit (LEO) constellations is dominated by propagation delay, making total delay roughly proportional to the network diameter, the longest shortest path in hops. Current inter-satellite link (ISL) layouts have rarely been optimized to minimize network diameter while simultaneously satisfying physical and operational constraints, including maximum link distance, line-of-sight, per-satellite hardware limits, and long-term link viability over orbital periods. In this study, the selection and assignment of inter-plane ISLs is formulated as a diameter-minimization problem on a Starlink-inspired Walker-Delta constellation in which each satellite is equipped with two fixed intra-plane links and may activate up to two inter-plane links. Beginning with a feasible baseline, the topology is iteratively refined by a local-search procedure that replaces or reinforces links to shrink the diameter. The resulting ISL configuration meets all geometric and hardware limits, preserves link stability across multiple orbital periods, and yields a sparse, diameter-aware graph with potential for centralized routing capabilities. Simulations demonstrate that the proposed algorithm achieves low worst-case latency without compromising ISL stability, and the trade-off between hop count and long-term link stability is empirically measured for guidance of future LEO network deployments.

Inter-Satellite Link Configuration for Fast Delivery in Low-Earth-Orbit Constellations

TL;DR

This work tackles latency optimization in large LEO satellite constellations by formulating inter-plane ISL selection as a diameter-minimization problem under realistic geometric and hardware constraints. It proposes an iterative local-search algorithm that starts from a baseline topology with two intra-plane links per satellite and up to two inter-plane links, refining inter-plane connections to reduce the network diameter while ensuring long-term link viability. The study analyzes two operational models: a snapshot-only feasibility model and a viability-constrained model that enforces link validity over an orbital period, revealing a clear trade-off between low latency and topology stability. Simulation results show that snapshot-only designs achieve smaller diameters but higher link churn, whereas viability-constrained designs provide robust, deployable topologies with higher worst-case latency, guiding design choices for centralized routing in mega-LEO constellations.

Abstract

End-to-end latency in large low-Earth-orbit (LEO) constellations is dominated by propagation delay, making total delay roughly proportional to the network diameter, the longest shortest path in hops. Current inter-satellite link (ISL) layouts have rarely been optimized to minimize network diameter while simultaneously satisfying physical and operational constraints, including maximum link distance, line-of-sight, per-satellite hardware limits, and long-term link viability over orbital periods. In this study, the selection and assignment of inter-plane ISLs is formulated as a diameter-minimization problem on a Starlink-inspired Walker-Delta constellation in which each satellite is equipped with two fixed intra-plane links and may activate up to two inter-plane links. Beginning with a feasible baseline, the topology is iteratively refined by a local-search procedure that replaces or reinforces links to shrink the diameter. The resulting ISL configuration meets all geometric and hardware limits, preserves link stability across multiple orbital periods, and yields a sparse, diameter-aware graph with potential for centralized routing capabilities. Simulations demonstrate that the proposed algorithm achieves low worst-case latency without compromising ISL stability, and the trade-off between hop count and long-term link stability is empirically measured for guidance of future LEO network deployments.

Paper Structure

This paper contains 14 sections, 3 equations, 2 figures, 2 tables, 1 algorithm.

Table of Contents

  1. Introduction
  2. Related Work
  3. System Model
  4. Problem Formulation
  5. ISL Topology Design
  6. Initial Topology Construction
  7. Iterative Topology Optimization
  8. Simulation & Results
  9. Performance Benchmarks
  10. Snapshot-Only Variant Results
  11. Viability-Constrained Variant Results
  12. Topology Visualization and Link Stability
  13. Discussion
  14. Conclusions

Figures (2)

  • Figure 1: A 3D visualization of the optimized LEO constellation in the viability-constrained model. Intra-plane links are shown in green, while inter-plane links are shown in blue. One of the longest shortest paths is highlighted in red, illustrating the network diameter.
  • Figure 2: Link distances over time for the highlighted longest shortest path. Intra-plane links (dashed lines) maintain a constant distance, while inter-plane links (solid lines) vary. All links remain below the $d_{\max}$ threshold.