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 OverThe-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.