The present invention relates to a method of synchronizing a plurality of base stations in a wireless telecommunications system (100) comprising base stations (BS1 to BS5) interconnected by an IP architecture local area network (10), the method including a step of hierarchical organization carried out in each group of base stations (BS1 to BS4) covering interconnected picocells (P1 to P4) by assigning positive integer numbers (No.1 to No.4) in increasing order and a fine synchronization step involving listening to a lower numbered base station of its group.