ENVELOPE Greek Trial Site in Athens Demonstrates Seamless Cross-Network Connectivity

Imagine driving an autonomous vehicle across multiple countries. As it moves from one mobile network to another, its safety-critical systems remain fully operational and continuously connected to traffic management services through guaranteed, low-latency communications. This seamless and guaranteed connectivity is exactly what researchers at the Greek trial site of the ENVELOPE project are working to make a reality.

ENVELOPE is a European Union-funded research project focused on making mobile networks smarter and more efficient, so that they can better support the connected vehicles and automated services of tomorrow. The Greek team, led by the National Centre for Scientific Research “Demokritos” (NCSRD) together with Greek telecom operator OTE and partners ICCS, FOGUS, HPE and ISFM is tackling one of the hardest challenges in this space: keeping a vehicle’s applications and safety data flowing seamlessly when it moves between two 5G networks.

What Has Been Achieved So Far

The trial environment in Athens is now fully operational. Two independent 5G networks, one operated by OTE and the other by NCSRD, have been deployed along a real outdoor route on the NCSRD campus. In parallel, a suite of smart software components has been integrated to support capabilities such as network quality prediction, traffic steering, edge application management and real-time vehicle location. Together, these technologies ensure continuous service availability as vehicles move across network domains.

The team has already successfully demonstrated the network handover between the two 5G infrastructures, with the vehicle onboarded application automatically rediscovering and reconnecting to the nearest server in the new network domain. An Android mobile application running in the vehicle collects and shares real-time data, including speed, position and situational alerts such as emergency braking warnings, all while roaming between operators.

What Is Being Worked on Now

The team is currently focused on further enhancing the reliability of the service continuity as vehicles move between the two 5G networks. Ongoing work includes optimizing radio coverage and signal quality along the test route, while refining intelligent traffic-steering mechanisms that dynamically select the most suitable connectivity path based on real-time network conditions.

What Comes Next

The next major milestone is the arrival of the autonomous shuttle vehicle provided by MILLA, at the NCSRD campus in September 2026. Once on-site, the team will run the full end-to-end trials, putting the entire system to the test under real-world conditions and collecting the final performance results that will demonstrate the Greek use case. These results will contribute directly to the broader goals of ENVELOPE and inform the future of connected mobility across Europe.