Patent ID: 8116405

Claim:
A time synchronization method using Global Positioning System (GPS) information in a communication system, the method comprising the steps of: (a) extracting 1 Pulse Per Second (PPS), Time Of Day (TOD), 1PPS_en, and oscillator clocks by using GPS signals by a grand master node having a GPS receiver, stabilizing the extracted signals, generating a sync message for time synchronization by using the stabilized signals, and transmitting the sync message to a slave node; (b) receiving the sync message by the slave node and conducting a time synchronization operation by using Offset & Frequency Compensation Clock (OFCC) synchronization technology supporting separate compensation of time offset and frequency by a time synchronization block of the slave node so that TOD information of the time synchronization block is modified, wherein a time compensation interval (TCI) and a frequency compensation interval (FCI) are set so that the TCI comprises an interval of two adjacent sync messages and the FCI is longer than the TCI; (c) extracting 1PPS, TOD, and 1PPS_en signals by using the modified TOD information by the time synchronization block and delivering the extracted signals to a stabilization block of the slave node so that the extracted signals are stabilized; and (d) delivering the stabilized signals to the time synchronization block again to update TOD information of the time synchronization block and generating a sync message for time synchronization of a second slave node by using the updated TOD information.