Case study: TRANTOR
The Evolution to Multi-Orbital Multi-Band Networks (TRANTOR) project was initiated with the overarching goal of ensuring trustworthy connectivity for future 5G+ and 6G networks in order to strengthen Europe’s position in secure communications.
The project consortium focused on building secure and resilient multi-orbital, multi-band networks by addressing the challenges presented by the integration of terrestrial, satellite and hybrid communication systems, in particular interoperability, performance and cybersecurity.
Starion played a leading role in TRANTOR’s research and development activities on advancing security in next-generation communication systems.
Timeline
- January 2023 – 36-month project starts
- July 2026 – Final demo following project extension
Stakeholders
Coordinated by Centre Tecnologic De Telecomunicacions De Catalunya, the project partners were:
- Fraunhofer Gesellschaft Zur Forderung Der Angewandten Forschung
- Hispasat
- Software Radio Systems
- Inster Tecnologia Y Comunicaciones
- Consiglio Nazionale Delle Ricerche
- Indra Sistemas
- Universite Du Luxembourg
- QuadSAT
- Starion Luxembourg
Objectives
Terrestrial mobile networks always met a common set of standards, allowing users on different networks to communicate with each other. This wasn’t the case with satellite communication systems, limiting the opportunity to extend mobile network coverage by using non-terrestrial networks (NTNs), for example in areas where terrestrial networks were poor or non-existent.
TRANTOR was a multi-year European project (2023–2026) established to address this by focusing on building secure and resilient 5G+ networks that were not limited to specific satellite bands or orbits. The project brought together leading European experts in telecommunications, cybersecurity and space systems to develop solutions to the challenges associated with interoperability, performance and cybersecurity in future communication infrastructures.
TRANTOR had six specific objectives:
- Adoption of 5G Advanced and pre-6G NTNs by satellite operators – Accelerate innovation in 5G satellite networks and ground equipment, and ultimately help operators provide better connectivity for communities around the world
- Provide novel satellite components for 5G Advanced NTNs
- Development of 5G Advanced NTN user equipment and Next Generation Node B (base stations for 5G; gNodeB)
- Development of artificial intelligence (AI) governance modules for resource management
- Creation of mission planner for the design of future satellite networks, with scalable optimisation techniques for resource allocation
- Secure satellite operator network – Research and development of a network security keeper with a threat risk assessor, trust access unit for static risk mitigation and security operations centre (SOC).
Innovation and implementation
Starion’s contribution to TRANTOR centred on analysis of the 3rd Generation Partnership Project (3GPP) security architecture for NTNs, identifying vulnerabilities and assessing potential threats within the TRANTOR framework. This work provided the foundation for the development of advanced methodologies for the risk assessment and security monitoring specifically tailored to NTN environments.
Building on these methodologies, Starion developed the ‘Security Keeper’, an innovative platform designed to assess the security posture of the entire system. It did so by performing real-time risk assessment, vulnerability detection and anomaly analysis, enabling operators to evaluate evolving threats and maintain an up-to-date view of the overall system risk through its full life cycle.
By providing continuous and contextualised awareness rather than static security verification, this solution supports informed decision-making and enhances the resilience of integrated terrestrial and non-terrestrial communication networks.
Results and impact
Six demonstrations took place during the TRANTOR project, with Starion actively involved in two of these. The first three looked at end-to-end single band connectivity using:
- A single geostationary Earth orbit (GEO) satellite
- A single drone-emulated low Earth orbit (LEO) satellite
- On-board processing capabilities of a satellite with centralised/distributed unit (CU/DU) splitting.
The remainder covered:
- Multi-band transmission from a single GEO satellite – This scenario was an extended multi-end case, where the user equipment has advanced capabilities to receive in multiple bands, specifically Ku and Ka. Starion was involved because during the demo, an attack was simulated and, in accordance with the alert generated by the Security Keeper (developed by Starion), a change of band was triggered to maintain the secure status of the communication.
- Multi-orbital, multi-band transmission using a GEO and a drone-emulated LEO satellite – This scenario put together all the previous scenarios, with a multi-band transmission from a LEO and a GEO satellite. Starion’s experts were involved to oversee and analyse the secure status of the communication.
- Multi-satellite, multi-band transmission using two GEO satellites.
During the project, the Starion team faced a number of challenges, including: the complex integration of terrestrial, satellite and hybrid networks; rapidly evolving cyber threats; ensuring data privacy and regulatory compliance; maintaining interoperability and performance across systems; and real-time monitoring.
They addressed these using innovative solutions employing cross-layer security protocols, security automation and orchestration, and visualisation and reporting tools.
The practical demonstrations carried out as part of the TRANTOR project successfully validated the new security technologies developed by Starion’s team, demonstrating their ability to actively identify and mitigate vulnerabilities in real-world scenarios. These in-depth tests demonstrated that Security Keeper was a key component in ensuring the proper functioning of the system as a whole, guaranteeing that the services supporting future communications would operate in a secure and resilient environment.
The impact of the technology developed by Starion extends beyond the practical sphere into the scientific community. Starion’s experts published a paper in collaboration with the University of Luxembourg entitled ‘Real-Time IDS for 5G-NTN: a First Step Towards a New IDS Framework’, which was presented at the Eupisco 2025 conference.
Final demonstration
What’s next?
TRANTOR is a decisive step towards the future of global secure communications. Its outcomes will influence the evolution of 5G+, 6G and satellite-enabled networks, creating a robust and trustworthy communication infrastructure. By integrating advanced security research with practical demonstrations, TRANTOR is shaping a connected future where safety and resilience are built in from the start.
Starion leaves the project with new and reinforced expertise in the domain and is ready to apply the skills gained to future projects, including the design of secure-by-default novel telecommunication technologies.
Notes
The TRANTOR project received funding from the European Union’s Horizon Europe research and innovation programme, specifically Horizon 2.4.10 (Space, including Earth observation) under grant agreement No 101081983.