A method, apparatus, and computer program for authenticating a newly activated local area base station in a cellular network is presented. The newly activated local area base station, associated with a sub-cell located within a coverage area of a wide area base station of a cellular telecommunication system, is paired with the wide area base station on the basis of information enabling identification of the wide area base station and originating from the local area base station. Then, transfer of a radio communication identifier to the local area base station is arranged over a wired connection.