Abstract: A method and system for transmitting timing advance data to a mobile station in cellular mobile radio network and corresponding mobile station, base station controller and transmission system. The method and system of the invention applied to a cellular mobile radio network including a mobile station, at least two base transceiver stations and a base station controller. The exchanges of information between the mobile station and the stations are of the time-division multiple access type. The controller transmits to the mobile station via a first station with which the mobile station is communicating an instruction telling it to interrupt communication with the first station in order to send a sequence of synchronization signals to a second station, enabling the second station to calculate a timing advance.