Method for holding every antenna port downlink data synchronization of the same base station

The invention relates to a method for keeping the descending data synchronous of each antenna port in one base station, which comprises: RE, based received CPRI frame and the delay time that sending CPRI frame from the REC timed reference point to the RE timed return reference point, builds the BFN timed reference of RE; REC builds the time that said descending data reaches the RE antenna port when sending descending data to RE; RE, based on said time, and the rebuilt BRF timed reference, sends out the descending data, to make the time that the data reaches antenna port as the appointed time. The invention can confirm the synchronization between the antenna ports of each region of one base station, to avoid the descending data transmission delay inside REC.