Patent ID: RE41000

Claim:
A method in a cellular radio communications system, which is arranged for communicating information in data frames (DF) of a predetermined duration (T ƒ ) the system comprising at least one central node (RNC 1 , RNC 2 ) and at least one asynchronous base station (BS 1 -BS 5 ), for synchronizing all base stations (BS 1 , BS 2 ) that are connected to one (RNC 1 ) of the at least one central node (RNC 1 , RNC 2 ) independently of any global time reference for the system, the method comprising the steps of: sending a system frame counter state (SFC) from the central node (RNC 1 ) to all its connected base stations (BS 1 , BS 2 ), the frame counter state being incremented one step for each of the data frames (DF); and aligning in each of the connected base stations (BS 1 , BS 2 ) a state of a respective local frame counter (LFC BS1 , LFC BS2 ) with the system frame counter state (SFC); wherein each of the data frames (DF) is associated with a specific frame number (t 1 ( 1 )-t 1 ( 4 ), t 2 ( 1 )-t 2 ( 4 )) which is derived from the responsive local frame counter (LFC BS1 , LFC BS2 ).