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A Novel Non-Terrestrial Networks Architecture: All Optical LEO Constellations with High-Altitude Ground Stations

Pablo G. Madoery, Juan A. Fraire, Jorge M. Finochietto, Halim Yanikomeroglu, Gunes Karabulut Kurt

TL;DR

This work tackles the weather-limited feasibility of all-optical LEO constellations by introducing high-altitude ground stations (HAGS) that serve as elevated relay and buffering nodes. The authors model and simulate two architectures—traditional GS and HAGS-based—and show that HAGS can preserve delivery ratio and reduce delivery delays under cloud cover using store-carry-forward DTN techniques and CGR routing, with links operating at 8 Gbps. A cloud-cover model using $TCC=1/\mu$ and a mean clear-sky time $TCS$ underpins the analysis, and an SVM-based equivalency analysis demonstrates that a couple of HAGS can match the performance of a larger GS array in several regimes. The findings suggest HAGS as a viable path to scalable, all-optical LEO mega-constellations, while also outlining challenges in buffer management, topology design, and optical link maintenance for practical deployment.

Abstract

The emergence of low Earth orbit (LEO) satellite mega-constellations is dynamically transforming the space sector. While free-space optical (FSO) links efficiently facilitate intersatellite data forwarding, they suffer from atmospheric/weather conditions in the space-to-ground link. This study delves into utilizing high-altitude platform stations (HAPS) as elevated relay stations strategically positioned above terrestrial ground stations. We introduce the concept of high-altitude ground stations (HAGS), an innovative approach to enabling the development of all optical LEO satellite constellations. The first contribution is an analysis of the HAGS-based network architecture where the LEO spacecraft only hosts FSO transceivers. Secondly, we execute an extensive simulation campaign to determine the gain of HAGS, including a new equivalency model with the traditional ground station approach. Finally, we examine the research challenges of implementing HAGS-based, all optical LEO mega-constellations.

A Novel Non-Terrestrial Networks Architecture: All Optical LEO Constellations with High-Altitude Ground Stations

TL;DR

This work tackles the weather-limited feasibility of all-optical LEO constellations by introducing high-altitude ground stations (HAGS) that serve as elevated relay and buffering nodes. The authors model and simulate two architectures—traditional GS and HAGS-based—and show that HAGS can preserve delivery ratio and reduce delivery delays under cloud cover using store-carry-forward DTN techniques and CGR routing, with links operating at 8 Gbps. A cloud-cover model using and a mean clear-sky time underpins the analysis, and an SVM-based equivalency analysis demonstrates that a couple of HAGS can match the performance of a larger GS array in several regimes. The findings suggest HAGS as a viable path to scalable, all-optical LEO mega-constellations, while also outlining challenges in buffer management, topology design, and optical link maintenance for practical deployment.

Abstract

The emergence of low Earth orbit (LEO) satellite mega-constellations is dynamically transforming the space sector. While free-space optical (FSO) links efficiently facilitate intersatellite data forwarding, they suffer from atmospheric/weather conditions in the space-to-ground link. This study delves into utilizing high-altitude platform stations (HAPS) as elevated relay stations strategically positioned above terrestrial ground stations. We introduce the concept of high-altitude ground stations (HAGS), an innovative approach to enabling the development of all optical LEO satellite constellations. The first contribution is an analysis of the HAGS-based network architecture where the LEO spacecraft only hosts FSO transceivers. Secondly, we execute an extensive simulation campaign to determine the gain of HAGS, including a new equivalency model with the traditional ground station approach. Finally, we examine the research challenges of implementing HAGS-based, all optical LEO mega-constellations.
Paper Structure (11 sections, 5 figures)

This paper contains 11 sections, 5 figures.

Table of Contents

  1. Introduction
  2. Background
  3. System Model
  4. Evaluation and Analysis
  5. Results Analysis
  6. Delivery Ratio
  7. Delivery Delay
  8. Buffer Occupation
  9. Equivalency Analysis between GS and HAGS
  10. Open Challenges
  11. Conclusion

Figures (5)

  • Figure 1: Opportunities of HAGS: enhanced visibility time and weather impairment buffer.
  • Figure 2: Downlink data handling and operations in traditional FSO and our HAGS approach.
  • Figure 3: Delivery delay for different TCS and TCC values.
  • Figure 4: Delivery delay for different TCS and TCC values.
  • Figure 5: Equivalency Analysis between GS and HAGS.