5G-NTN prototyping and experimentation results

The integration of 5G with a Non-Terrestrial Network (NTN) promises to achieve ubiquitous connectivity. Although the coverage of satellites is significantly larger, unfortunately, protocol development under the regimes of terrestrial and satellite

communication has been done under exclusivity, hence, preventing experiencing the best of both worlds. In the recently frozen 3GPP Release 17, a significant leap has been taken by including satellites in the 5G-NR ecosystem. In this regard, Proof-of-

Concept (POC) demonstrators, especially which are based on open-source implementation can play a key role in expediting the ongoing 5G-NTN research. In this paper, we discuss the goals, key achievements, and ongoing activities related to two 5G-NTN projects (a) 5G-GOA: 5G-Enabled Ground Segment Technologies

Over-The-Air Demonstrator and (b) 5G-LEO: OpenAirInterface Extension for 5G Satellite Links. In both projects, the aim is to provide direct access of 5G to a ground UE via a transparent payload satellite (GEO for 5G-GOA and LEO for 5G-LEO). An

open-source implementation of terrestrial 5G-NR RAN protocol stack from OpenAirInterface has been taken as the baseline and adaptations have been done in all the layers to address the challenges such as large Round-Trip-Time (RTT), high and

variable Doppler, frequent handover, re-transmissions, etc. The adaptations closely comply with the 3GPP Release-17 5G-NTN specifications. An end-to-end software simulator and hardware demonstrator have been developed and in-lab validation and overthe-satellite testing have shown promising results confirming the feasibility of direct access to 5G services via satellites.