A remote mobile network part (2, 11, 12) may be on an aircraft, a ship, or in a geographically remote location. It comprises a gateway (6) which communicates with a central gateway (9) via a satellite link. The two gateways (6, 9) together are a base station controller (BSC), the satellite link being used for BSC-internal communication. Such communication can be optimised to make best use of the limited bandwidth available on the satellite link.