5G NR Non-Terrestrial Networks: From Early Results to the Road Ahead
This study addresses the critical applications of 5G non-terrestrial networks (NTN) in remote coverage, emergency communications, and terrestrial traffic offloading. It systematically reviews the 3GPP NR-NTN standardization evolution from Release 18 to Release 20 and proposes an innovative architecture tailored for Release 20. Leveraging the ns-3 simulation platform, the work develops a high-fidelity satellite communication model—encompassing both low Earth orbit (LEO) and geostationary orbit (GEO) constellations—calibrated with 3GPP-standardized parameters and real-world scenario data. Comprehensive performance evaluations across diverse network configurations demonstrate that the proposed architecture achieves significant improvements in wide-area coverage and network resilience, thereby providing key technical enablers for integrated space-air-ground 5G networks.