5G-NTN GEO-based In-lab demonstrator using OpenAirInterface5G

The integration of 5G with Non-Terrestrial Network (NTN) components is going through a series of technological advancements and soon satellites will be a part of the 5G ecosystem. Early demonstrators, especially based on open-source implementations, are essential to support further research. In this work, we discuss the ongoing activities and developments related to the project 5G-Enabled Ground Segment Technologies Over-The-Air Demonstrator (5G-GoA) which has been funded under the ESA-ARTES program. The vision of 5G-GoA is developing and implementing suitable modifications in the 5G New Radio (NR) standard for enabling direct radio access to 5G services

using a transparent GEO satellite. For this purpose, we have used OpenAirInterface(OAI) which is a Software Defined Radio (SDR) based open-source implementation of the 5G-NR protocol stack. We adapted it to address the challenges caused by the excessive round-trip delay in GEO satellites. Our solutions encompass all the layers of the 5G protocol stack: The physical layer (e.g. synchronization) up to upper layer implementations (e.g. timers and random-access procedure) of the Radio Access Network. Our modifications comply with the specifications mentioned for 5GNTN in the recently frozen 3GPP Release-17. An end-to-end demonstrator has been developed for in-lab validation over a satellite channel emulator prior to over-the-satellite testing. Our initial experiments show promising results and the feasibility of direct access to 5G services through transparent GEO satellites.