An In-Depth Investigation of LEO Satellite Topology Design Parameters

TL;DR

This work systematically investigates how three LEO topology design parameters—number of orbits per shell, orbital inclination, and satellites per orbit—impact ISL-enabled network performance. By evaluating both real constellations (Starlink, Kuiper, Telesat) and a wide range of synthetic configurations against a GDP-city traffic matrix, the authors identify key thresholds (approximately 28 satellites per orbit and 33 orbits) and demonstrate that latency is significantly influenced by the alignment between endpoint geographic angles and orbital inclination. The study shows that higher-density shells do not always yield better performance, and that aligning the constellation’s inclination with traffic geography can reduce hops and latency. These insights, along with open-source code, offer practical guidance for future LEO mega-constellation design and routing/traffic engineering strategies.

Abstract

Low Earth Orbit (LEO) satellite networks are rapidly gaining traction today. Although several real-world deployments exist, our preliminary analysis of LEO topology performance with the soon-to-be operational Inter-Satellite Links (ISLs) reveals several interesting characteristics that are difficult to explain based on our current understanding of topologies. For example, a real-world satellite shell with a low density of satellites offers better latency performance than another shell with nearly double the number of satellites. In this work, we conduct an in-depth investigation of LEO satellite topology design parameters and their impact on network performance while using the ISLs. In particular, we focus on three design parameters: the number of orbits in a shell, the inclination of orbits, and the number of satellites per orbit. Through an extensive analysis of real-world and synthetic satellite configurations, we uncover several interesting properties of satellite topologies. Notably, there exist thresholds for the number of satellites per orbit and the number of orbits below which the latency performance degrades significantly. Moreover, network delay between a pair of traffic endpoints depends on the alignment of the satellite's orbit (Inclination) with the geographic locations of endpoints.

Figures (37)

• Figure 1: Parameters of LEO constellation.
• Figure 2: Distribution of maximum RTT (ms) across top 100 city pairs using Starlink S1 and Custom-designed topology, Example E1 .
• Figure 3: The network performance of Starlink shells 1-5 (S1-S5) of Phase I. For all curves, lower values indicate better performance. Long tails indicate outliers with poor performance. The tail of S5 is truncated in (d) due to a very high number of path changes.
• Figure 4: The network performance of shells 1-3 (K1-K3) of Kuiper and shell 1 and 2 (T1, T2) of Telesat. For all curves, lower values indicate better performance. Long tails indicate outliers with poor performance.
• Figure 5: The distribution of Maximum RTT(ms) while varying the number of satellites per orbit (Sats/Orbit). For all curves, lower values indicate better performance. Long tails indicate outliers with poor performance.