Quantum Routines In Space-Terrestrial Integrated Networks

Coach Name

Juan Juan

EU Organization

Fondazione LINKS (Italy)

Members

  • Chiara Vercellino
  • Giacomo Vitali
  • Paolo Viviani
  • Alberto Scionti
  • Olivier Terzo

US Organization

QuEra Computing (USA)

Members

  • Tommaso Macrì

Project Overview

QRISTIN explores how quantum optimization algorithms can help solve complex problems in Space–Terrestrial Integrated Networks (STINs) — hybrid communication infrastructures combining terrestrial links (cell towers, fiber) with satellite systems. These networks are essential for extending connectivity to rural and underserved areas, but their design and operation require solving extremely challenging combinatorial optimization problems.

The project developed an open-source solver that models STIN optimization tasks and solves them using either classical, hybrid, or quantum routines, enabling fair side-by-side comparisons of performance, runtime, and scalability. This solver, available in a public GitLab repository, brings transparency and reusability to the research community.

QRISTIN benchmarked its algorithms on 165 problem instances, far above its original goal, demonstrating that quantum-enhanced approaches can outperform classical heuristics by up to 31.2%, with an average improvement of 9.2%.

Methods and approaches

Hybrid Quantum–Classical Optimization Framework

The project designed a unified solver integrating classical heuristics with NISQ-compatible quantum routines. Three STIN-related subproblems (SSP, GSP, SAP) were formally defined and implemented, and embedding methodologies were created to map them onto QuEra’s Aquila QPU.

Extensive Modeling, Validation & Benchmarking

QRISTIN validated performance over 165 problem instances, comparing quantum, hybrid, and classical solvers using open datasets for terrestrial and satellite networks. Scenario modeling, quantum noise mitigation, and post-processing techniques were used to ensure robust and reproducible results.

Key Achievements

Developed an open-source STIN optimization solver integrating classical, hybrid, and quantum routines (70+ commits).

Defined three quantum-suitable subproblems and implemented NISQ-consistent quantum embeddings for QuEra hardware.

Achieved performance gains up to 31.2%, average 9.2%, versus classical heuristics across 165 problem instances.

Delivered major technical reports and software releases:

  • D1.1 STIN Optimization Problem
  • D2.1 Classical Methods & Quantum Routines
  • D2.2 QRISTIN Solver
  • D3.1 Quantum Optimization State of the Art
  • D3.2 Quantum Routines
  • D4.1 Benchmark & Validation

Disseminated results in five scientific events, including HiPEAC, PASQuanS2.1, Italian Research Day, University of Illinois Chicago, and the QuEra Quantum Alliance workshop.

Submitted a joint scientific publication: Quantum-Assisted Design of Satellite–Terrestrial Integrated Networks.

Completed the required 45 stakeholder interviews.

Impact & Results

Scientific Impact

QRISTIN provides a structured and validated framework for applying quantum optimization to real-world communication networks. It produced reusable software, documented methodologies, and benchmarked quantum devices in practical STIN scenarios.

Economic Industrial Impact

The project demonstrated that quantum-assisted optimization can improve efficiency in telecom infrastructure planning—particularly in underserved regions where STINs are crucial. Collaboration with TIM S.p.A., QuEra, and Pawsey Supercomputing Centre aligns research with industry needs.

Societal Impact

By improving connectivity design for remote regions, QRISTIN contributes to reducing the digital divide and strengthening future communication infrastructures.

Strategic Transatlantic Impact

The project reinforced EU–US collaboration through formal partnerships (MoU with QuEra, participation in the QuEra Quantum Alliance) and intends to pursue future joint funding.

Publications and Open-Source Contributions

  • Preprint: Quantum-Assisted Design of Satellite–Terrestrial Integrated Networks
  • Deliverables D1.1, D2.1, D2.2, D3.1, D3.2, D4.1, D5.1
  • GitLab repository containing the full solver stack, quantum routines, classical solvers, embeddings, datasets, and documentation
  • Presentations at:

    • HiPEAC CONCERTO Workshop
    • PASQuanS2.1
    • Italian Research Day (Chicago)
    • University of Illinois Chicago Seminar
    • QuEra Quantum Alliance Workshop

Future directions

Fondazione LINKS and QuEra plan to:

  • Further improve quantum-classical hybrid routines and noise-mitigation methods.
  • Extend the solver to additional STIN scenarios and other communication-network problems.
  • Pursue new EU–US funding opportunities and strengthen industrial collaborations.
  • Continue contributing to open-source quantum optimization tools and scientific publications.

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Horizon Europe – Grant Agreement number 101092887

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Union’s Horizon Europe research and innovation programme. Neither the European Union nor the granting authority can be held responsible for them.