Patent ID: 7369768
Filing Date: 2008-05-06
Classification: H04J

Abstract:
1. An optical access system including: multiple Optical Network Terminals connected respectively to user terminals, each containing an interface for sending/receiving time-division multiplexed signals and packet multiplexed signals, and an interface for multiplexing the time-division multiplexed signals and packet multiplexed signals and sending/receiving the multiplexed signals; and an Optical Line Terminal connected to a network and the Optical Network Terminals via a splitter and an optical fiber, and said Optical Line Terminal containing an interface for sending/receiving time-division multiplexed signals and packet multiplexed signals, and an interface for multiplexing the time-division multiplexed signals and packet multiplexed signals and sending/receiving the multiplexed signals, wherein the Optical Network Terminals and the Optical Line Terminal communicating with each other with first periodic frames and performing a ranging for measuring a distance between the Optical Line Terminal and the Optical Network Terminals, wherein when sending signals from one of the Optical Network Terminals to the Optical Line Terminal, said one Optical Network Terminal transmits the time-division multiplexed signals with second periodic frames each period of which being longer than a period of the first periodic frame and containing a fixed number of the first periodic frames transmitted from one of the user terminals to said one Optical Network Terminal, and transmission of the second periodic frames is scheduled so that the timing not is not overlapped with a ranging time during which the ranging is being performed, and when sending signals from the terminal Optical Line Terminal to one of the Optical Network Terminals, the Optical Line Terminal transmits the time-division multiplexed signals with the second periodic frames each period of which being longer than the period of the first periodic frame and containing a fixed number of the first periodic frames transmitted from the Optical Line Terminal to one of the user terminals, and transmission of the second periodic frames is scheduled so that the timing is not overlapped with the ranging time.