Radio interface protocols and radio resource management procedures for 5G new radio non‐terrestrial networks

Summary In Release 17, 3GPP introduced adaptations and enhancements to the 5G new radio (NR) specification to support non‐terrestrial networks (NTNs) operation. The main challenges were due to long propagation delays, especially in GEO deployments, and the movement of the satellites in LEO deployments. In this paper, we give an overview of the protocol adaptations to support NTNs. The main user plane protocol adaptations include changes to random access and hybrid automatic repeat request to due long propagation delays. The control plane protocol adaptations include a variety of mobility related enhancements for user equipment. The third generation partnership project (3GPP) standardization group has finalized the very first mobile communication standard enabling efficient 5G NR connectivity via satellite access. This paper presents the key enhancements from protocol specification perspective which controls the air interface connections between gNB and the user equipment.