Patent ID: 7873277
Filing Date: 2011-01-18
Classification: H04J

Abstract:
1. A passive optical network system which comprises an optical line termination, an optical splitter, an optical fiber, and a plurality of optical network units connected to the optical line termination through the optical splitter and in which the optical line termination communicates with the optical network units in wavelength division multiplexing, wherein the system includes a plurality of wavelengths for communication between the optical line termination and the optical network units, a first wavelength among the plurality of wavelengths is previously determined as a wavelength for transmission and reception of a control message, and a second wavelength for communication with each of the optical network units is assigned among the plurality of wavelengths including the first wavelength, wherein the optical line termination includes: a plurality of first transmitters having light source respectively which wavelengths are different from each other; a plurality of first receivers to receive signals of a plurality of wavelengths; a wavelength management table to manage information of the second wavelength assigned for communication with each of the optical network units for each of identifiers of the optical network units; and a first control unit to transmit and to receive a first and a second control messages for assigning wavelengths to and from the optical network unit and to assign the second wavelength for the communication with the optical network unit, wherein each of the optical network units includes: a second receiver to receive a signal of a set wavelength; a second transmitter to transmit a signal of a set wavelength; a second control unit to transmit and receive the first and the second control message to assign the wavelengths through the second transmitter and the second receiver; and a wavelength control unit to variably control the transmission wavelength of the second transmitter and the reception wavelength of the second receiver to the first wavelength or the second wavelength, and wherein the optical network unit transmits the first control message to request assignment of the second wavelength to be used for communication between the optical line termination and the optical network unit itself to the optical line termination by the second transmitter previously set to the first wavelength, when the optical line termination receives the first control message from the optical network unit, the optical line termination refers to the wavelength management table, assigns the second wavelength, which is not assigned to other communications, to communication with the optical network unit, and transmits, by using the first wavelength, the second control message to notify information of assigned second wavelength to the optical network unit, the optical network unit receives the second control message by the second receiver previously set to the first wavelength, and sets the transmission wavelength of the second transmitter and the reception wavelength of the second receiver to the assigned second wavelength by the wavelength control unit based on the second control message, and the optical network unit and the optical line termination communicate with each other with the second wavelength.