ESA and Telesat have reported a groundbreaking milestone in telecommunications technology, successfully establishing the world's first 3GPP Non-Terrestrial Network (NTN) link over Low Earth Orbit (LEO) between the ESTEC 5G Laboratory and the Telesat LEO 3 satellite (thanks to a Memorandum of Understanding signed earlier this year between Telesat and ESA), using a Amarisoft 5G protocol stack. This remarkable achievement represents a significant leap forward in satellite communication technologies, demonstrating the operational viability of the new 5G NTN standard in LEO.
The research team, which brought together experts from the ESA Connectivity and Secure Communications, part of ESA’s Space for 5G/6G and Sustainable Connectivity programme line, and Technology, Engineering and Quality directorates, achieved a seamless telecommunications link with a satellite pass that maintained connectivity from approximately 10° elevation to a maximum of 80°, and concluding at around 30° to avoid the interference with the GEO arc.
Using a Amarisoft 5G protocol stack compliant with 3GPP NTN Release 17 specifications, in the ESTEC 5G Laboratory we have established a stable and bi-directional communication link between the gNB and the 5G NR NTN User Equipment (UE) on ground through the Telesat LEO3 satellite. Both downlink and uplink spectral efficiency reached the peak of 3 bits/s/Hz by enabling adaptive modulation and coding and selecting the digital modulation schemes from QPSK to 64-QAM. In addition, 32 HARQ processes have been activated to maximise the registered DL/UL throughput. Finally, thanks to the SIB19 information (e.g., the satellite ephemeris) transmitted through the LEO3 satellite, the Amarisoft 5G NR NTN UE has been able to maintain the correct frequency Doppler compensation and the uplink transmission timing for the entire satellite visibility period.
By promoting open standards through 3GPP protocols, ESA is driving a fundamental shift in how satellite communication systems are developed and deployed. The open approach to Non-Terrestrial Network technology promises multiple societal benefits.
By moving away from vertically integrated systems, this innovation introduces several critical advantages: An open ecosystem that accelerates technological development, elimination of vendor lock-in effects, and enhanced interoperability between terrestrial and satellite communication systems.
The most significant implication is the potential for consumers to access a wider range of communication terminals, moving beyond expensive, dedicated satellite equipment to more versatile and cost-effective solutions that use a standardised waveform. As satellite and terrestrial networks continue to converge, innovations like these will play a crucial role in connecting communities, supporting emergency response systems, and enabling new possibilities in sectors ranging from agriculture to disaster management, as well as paving the way for direct-to-device communication, benefiting users everywhere.
Antonio Franchi, ESA’s Head of the 5G/6G Non-Terrestrial Network (NTN) Programme Office within the Space for 5G/6G programme line, said: “This test is not just about technological capability, but about creating an open, collaborative ecosystem that will accelerate innovation and bring advanced communication solutions to people around the world. Congratulations to the ESA, Telesat and Amarisoft teams involved!”
Alberto Ginesi, Head of the Telecom Systems and Techniques Section of the Directorate of Technology, Engineering, and Quality (TEC) said: “This world-first experiment is the result of excellence in technical expertise and the impressive motivation and dedication of ESA TEC personnel to advance the technology in the area of broadband satellite access schemes. In particular, I would like to recognise the work of the Telecom Lab manager Augusto Marziani who carried out this experiment with the expert support of Stefano Cioni and Matteo Conti along with our industrial partners.
About two years ago, the 3GPP standardisation groups approved the 5G NR NTN specifications in Release 17, and today we have proudly demonstrated the benefits of this solution in a real NGSO satellite link. We are confident that this is only a first step, and many others will happen with the support of our ESA Member States. This achievement also demonstrates the ability of the European Space Agency to support the development, validation and verification of advanced satellite broadband networks, including the forthcoming European Commission IRIS2 project.”
Fabrizio De Paolis, ESA’s 5G/6G Implementation Manager, said “This ESA cross-directorate activity, combined with our industry partners showcases the high-level of expertise Europe possess when it comes to developing and delivering innovative NTN technologies. We’re incredibly proud of the team and look forward to seeing how we turn this demonstration into real societal and commercial benefits.”
Mario Neri, Telesat’s Director of Spectrum Strategy, Innovation and Space Sustainability said “This activity allowed testing the recently standardised 5G NTN technology in a real-world scenario, using the Ka-band spectrum over our LEO 3 satellite - something that no one had ever done before. This confirms Telesat’s engagement in constantly exploring innovative satellite technologies that can improve life on Earth.”
"Our team has once again pushed the boundaries of innovation, delivering advanced 3GPP features on schedule through our fully software-based technology. This versatile and flexible approach empowers seamless collaboration with leading teams like ESA and Telesat. Together, we proudly delivered a live demonstration that marks a significant step toward the future of non-terrestrial communication," said Marouan Benabdellah-Chaouni, Senior Vice President at Amarisoft.
