Patent ID: 8780886

Claim:
A computer-implemented data transmission synchronization method for a wireless communication system base station that includes a remote radio head (RRH) and a baseband unit (BBU) which are communicably connected through a network, wherein the BBU is used to process and transmit downlink data to the RRH, the synchronization method comprising: measuring a time-delay for the downlink data to arrive at the RRH from the BBU; and notifying from the RRH to the BBU of time-delay data on the measured time-delay, wherein the time-delay data is used to advance the starting time for the BBU to process and transmit the downlink data by an amount of time obtained based on the notified time-delay data; wherein the RRH further comprises: a digital to analog (D/A) converter for transmitting the downlink data to a wireless communication device; a downlink unit for receiving the downlink data from the BBU; and a pulse generator for generating a downlink pulse T DL for triggering the D/A converter to transmit the downlink data to the wireless communication device; wherein the step of measuring a time-delay for the downlink data to arrive at the RRH from the BBU comprises: measuring a first time difference T d1 between the time when the D/A converter begins to transmit the downlink data to the wireless communication device and the time when a first data sample of a data frame of the downlink data arrives at the RRH, wherein the time-delay data comprises the first time difference T d1 ; and wherein the step of measuring the first time difference T d1 between the time when the D/A converter begins to transmit the downlink data to the wireless communication device and the time when the first data sample of the data frame of the downlink data frame arrives at the RRH further comprises: measuring the first time difference T d1 between the time when the downlink pulse T DL is generated and the time when the first data sample of the downlink frame from the BBU arrives at the downlink unit.