Difference between NTN gateway and Satellite Access Node

Both are critical components in 5G NTN network, but with different scopes.

NTN Gateway

• It is the ground based station that provides connectivity between the 5G Core Network (5GC) and the satellite in a 5G NTN system.
• It serves as the anchor point for the feeder link; the high capacity connection between the terrestrial network and the satellite.
• Transmits and receives data, control and synchronization signals through the feeder link.

Satellite Access Node (SAN)

• The Satellite Access Node (SAN) is a functional node located onboard the satellite that provides 5G radio access capabilities to UEs.
• Essentially, it is the spaceborne equivalent of a terrestrial base station (gNB).
• Manages the radio interface with the User Equipment (UE) over the service link.
• Performs RAN functions such as RRC, scheduling & link adaptation, handover & mobility management.
• Handles beam management, Doppler compensation, and timing alignment.
• Communicates with the NTN Gateway or 5G Core Network via a backhaul or feeder link.

Summary : The Gateway is the physical ground station, while the SAN is the logical network node providing satellite access, which includes the satellite payload itself.