A method for synchronizing between an access gateway and a plurality of base stations is provided, which comprises the following steps of: at the gateway, determining (S1) a synchronization period corresponding to a packet to be transmitted to the plurality of base stations, said synchronization period being used as a scheduling granularity of the base stations, adding (S2) information indicating the synchronization period to the header of the packet, and transmitting (S3) the packet to the plurality of corresponding base stations; and at each of the plurality of base stations, obtaining (S4), upon receipt of the packet, the synchronization period corresponding to the packet based on the information in the header of the packet, storing (S5) the packet in a buffer, determining (S6), at the time of scheduling, synchronization periods which have terminated before the time of scheduling based on the synchronization periods corresponding to the stored packets, and scheduling (S7) packets corresponding to the deter
