Patent ID: 8542995
Filing Date: 2013-09-24
Classification: H04J

Abstract:
1. A method for time synchronization of an optical network terminal (ONT), which is a connection apparatus of a service provider of a passive optical network system, and an optical line terminal (OLT), which is a transmitting/receiving apparatus of a service provider of the passive optical network system, comprising: shifting to a ranging state; receiving a ranging request message that comprises a first current time of the optical line terminal from the optical line terminal; calculating a first compensation time when a transmission delay is compensated at a time that the ranging request message is received; transmitting a serial number response message to the optical line terminal; calculating a second compensation time when the transmission delay is compensated at a time that the serial number response message is transmitted; receiving a ranging time message that comprises a second current time when the serial number response message from the optical line terminal is received; calculating an offset time from the first current time, the second current time, the first compensation time, and the second compensation time; and synchronizing a clock of the optical network terminal and a clock of the optical line terminal based on the offset time.