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arxiv: 2604.16092 · v1 · submitted 2026-04-17 · 💻 cs.NI

Toward EU Sovereignty in Space: A Comparative Simulation Study of IRIS 2 and Starlink

Alexander Bonora , Marco Giordani , Michele Zorzi This is my paper

Pith reviewed 2026-05-10 07:30 UTC · model grok-4.3

classification 💻 cs.NI
keywords satellite constellationsStarlinkIRIS 2non-terrestrial networksLEO networkscapacity simulationhandoversatellite mobility
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The pith

Simulations of Starlink and IRIS 2 reveal capacity, mobility, and handover tradeoffs in supporting global satellite connectivity.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper sets out to compare two distinct satellite constellation designs through detailed modeling. Starlink uses a dense low-Earth orbit network aimed at high-capacity broadband for general use, whereas IRIS 2 combines low, medium, and geostationary orbits to deliver secure and sovereign communications for government and critical needs. A simulation campaign then measures per-cell and per-user throughput, tracks how satellite movement and handovers affect ongoing links, and checks each system's ability to provide reliable worldwide coverage. These results matter because they clarify concrete design choices that shape whether future networks can meet both commercial performance goals and public resilience requirements. The work closes by outlining possible extensions to strengthen IRIS 2 deployments.

Core claim

After laying out the technical parameters of each system, the simulations demonstrate specific differences in achievable capacity per cell and per user, quantify the service interruptions caused by satellite motion and required handovers, and establish that both architectures can support global connectivity but with distinct emphases on throughput versus resilience and sovereignty.

What carries the argument

The comprehensive simulation campaign that models the orbital layers, user distributions, and link dynamics of both constellations to quantify capacity, mobility effects, and handover impacts.

If this is right

  • IRIS 2 could incorporate targeted orbit or beam adjustments to close capacity gaps while preserving its resilience advantages.
  • Starlink's dense LEO layout sets a benchmark for per-user throughput that multi-layer public systems must address in future phases.
  • Handover frequency in each design directly influences the continuity of critical communications services.
  • Both systems demonstrate viable paths to global coverage, but IRIS 2's multi-orbit approach aligns more closely with requirements for sovereign and secure infrastructure.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Public multi-orbit networks may offer a route to reduced reliance on single commercial providers for essential services.
  • The capacity-resilience split identified here could guide how 6G non-terrestrial networks allocate resources between private and governmental uses.
  • Extending the simulations to include variable user densities in remote regions would test the robustness of the reported global-coverage claims.

Load-bearing premise

The simulation models correctly reflect real differences in capacity, satellite motion, and handover behavior without hidden biases from traffic patterns or interference assumptions.

What would settle it

Field measurements from operational Starlink users or early IRIS 2 test satellites that show per-user data rates or handover failure rates differing by more than 20 percent from the simulated predictions under comparable conditions.

Figures

Figures reproduced from arXiv: 2604.16092 by Alexander Bonora, Marco Giordani, Michele Zorzi.

Figure 2
Figure 2. Figure 2: Per-UE downlink and uplink capacity for IRIS [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Visibility period for Low-LEO, LEO, and MEO satellites in IRIS² vs. [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: Downlink per-UE capacity, coverage, and propagation delay consid [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
read the original abstract

The evolution of 6th generation (6G) networks increasingly relies on satellite-based Non-Terrestrial Networks (NTNs) to extend broadband connectivity to remote and unserved regions, and to support public safety. In this paper we compare two representative and conceptually different satellite constellation architectures, namely Starlink and IRIS 2. Starlink is a commercial private Internet constellation by SpaceX, based on dense Low Earth Orbit (LEO) satellites. It is primarily designed to deliver high-capacity broadband services for civil applications, with performance targets comparable to those of terrestrial networks. In contrast, IRIS 2 is a planned public initiative to be deployed by the European Union, based on a multi-layer combination of LEO, Medium Earth Orbit (MEO), and Geo-stationary Earth Orbit (GEO) satellites. It is primarily designed to provide a secure, resilient, and sovereign infrastructure for government and critical communications. After describing the main technical characteristics of Starlink and IRIS 2, we run a comprehensive simulation campaign to evaluate the design tradeoffs between the two. Specifically, we evaluate the per-cell and per-user achievable capacity, the impact of satellite mobility and handover, and identify the capability of each architecture to support global and reliable connectivity. We also provide design suggestions for possible future IRIS 2 deployment extensions.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The paper describes the technical characteristics of the Starlink (dense LEO) and IRIS² (multi-layer LEO/MEO/GEO) satellite constellations, then presents results from a simulation campaign comparing per-cell and per-user achievable capacity, the effects of satellite mobility and handovers, and each system's ability to deliver global reliable connectivity. It concludes with design suggestions for future IRIS² extensions.

Significance. If the simulation results hold, the work could inform EU policy discussions on sovereign space infrastructure by quantifying architectural trade-offs between commercial high-capacity LEO systems and public multi-orbit secure systems. The comparative framing and focus on mobility/handover impacts address a timely 6G NTN topic; however, the lack of model details prevents assessment of whether the reported numbers reflect real system behavior.

major comments (2)
  1. [Simulation Campaign (post-characteristics section)] The central claims rest on a 'comprehensive simulation campaign' (Abstract and subsequent simulation section) that reports per-cell/per-user capacity, mobility/handover impacts, and global connectivity without specifying orbital element sets, antenna gain patterns, propagation/interference models, traffic generation, user density, or any calibration against public Starlink throughput measurements or IRIS² reference documents. This absence directly undermines reproducibility and validity of the design trade-off conclusions.
  2. [Simulation Campaign] No validation, error bars, or baseline comparisons are described for the reported capacity and handover results, making it impossible to determine whether differences between Starlink and IRIS² arise from architectural features or from unstated modeling assumptions.
minor comments (1)
  1. [Abstract and title] Notation for IRIS 2 vs. IRIS² is inconsistent between title, abstract, and body.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive feedback on our simulation campaign. We agree that greater methodological transparency is required to support the reproducibility of our comparative results and will revise the manuscript accordingly.

read point-by-point responses

  1. Referee: [Simulation Campaign (post-characteristics section)] The central claims rest on a 'comprehensive simulation campaign' (Abstract and subsequent simulation section) that reports per-cell/per-user capacity, mobility/handover impacts, and global connectivity without specifying orbital element sets, antenna gain patterns, propagation/interference models, traffic generation, user density, or any calibration against public Starlink throughput measurements or IRIS² reference documents. This absence directly undermines reproducibility and validity of the design trade-off conclusions.

    Authors: We acknowledge that the original manuscript described the simulation campaign at a high level without enumerating all modeling parameters. In the revised version we will add a dedicated 'Simulation Methodology' subsection that specifies: orbital element sets (public TLE data for Starlink and the multi-layer parameters proposed in EU IRIS² tender documents); antenna gain patterns (parabolic reflectors for user terminals and phased-array models for satellites); propagation models (free-space path loss augmented by atmospheric and rain attenuation); interference models (co-channel interference from visible satellites within the beam); traffic generation (Poisson arrivals with mean rates drawn from typical broadband usage profiles); and user density (uniform spatial distribution within each cell). We will also insert a calibration paragraph that compares simulated Starlink per-user throughputs against publicly available measurement datasets (e.g., Ookla and FCC reports) and references the official IRIS² technical specifications for the multi-orbit architecture. These additions will enable independent reproduction and strengthen the validity of the architectural trade-off conclusions. revision: yes

  2. Referee: [Simulation Campaign] No validation, error bars, or baseline comparisons are described for the reported capacity and handover results, making it impossible to determine whether differences between Starlink and IRIS² arise from architectural features or from unstated modeling assumptions.

    Authors: We agree that the absence of statistical validation and baselines limits interpretability. In revision we will augment the results section with Monte Carlo simulation outputs (minimum 100 independent runs per scenario) and will display error bars corresponding to one standard deviation (or 95 % confidence intervals) for all capacity and handover metrics. We will further introduce two explicit baseline comparisons: (i) a static single-satellite reference model that removes mobility and multi-satellite interference, and (ii) theoretical Shannon-capacity upper bounds computed from the same link budgets. These baselines will allow readers to isolate the contributions of constellation density, orbital layering, and handover procedures from any residual modeling choices. revision: yes

Circularity Check

0 steps flagged

No circularity: simulation outputs follow from input constellation parameters

full rationale

The paper's derivation consists of describing Starlink and IRIS 2 technical characteristics from public sources, then running a simulation campaign to compute per-cell/per-user capacity, mobility/handover effects, and global connectivity. No equations, parameters, or results are shown to reduce by construction to fitted outputs, self-definitions, or load-bearing self-citations; the simulation results are computed forward from the stated architecture inputs without the forbidden patterns.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Only abstract available; no explicit free parameters, axioms, or invented entities are stated in the provided text.

pith-pipeline@v0.9.0 · 5537 in / 966 out tokens · 40515 ms · 2026-05-10T07:30:40.903890+00:00 · methodology

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Reference graph

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