Abstract: An optical line terminal (OLT) accumulates and stores a user frame for each physical layer identifier (PLID) to efficiently use a plurality of lanes used for downstream transmission from the OLT to an optical network unit (ONU). The OLT envelopes payloads that are accumulatively stored for the respective PLIDs based on a transmission rate supported by a corresponding ONU, combines an envelope header based on an envelope payload unit, and transmits an envelope frame. The OLT selects an available lane from among a plurality of lanes and may transmit the envelope frame through the selected lane.

Abstract: A method of registering an optical network unit (ONU) in an optical line terminal (OLT). The OLT determines a lane to be used by the ONU based on a transmission rate supported by the ONU, combines or distributes data of a dataflow based on a rate of the lane by comparing the rate of the lane to a rate of the dataflow of a media access control (MAC) client interface, and, when the OLT and the ONU are connected through multiple lanes, transmits and receives data between the OLT and the ONU through channel bonding for more effective use of a network.

Abstract: A method of registering an optical network unit (ONU) in an optical line terminal (OLT). The OLT determines a lane to be used by the ONU based on a transmission rate supported by the ONU, combines or distributes data of a dataflow based on a rate of the lane by comparing the rate of the lane to a rate of the dataflow of a media access control (MAC) client interface, and, when the OLT and the ONU are connected through multiple lanes, transmits and receives data between the OLT and the ONU through channel bonding for more effective use of a network.

Abstract: An optical line terminal (OLT) of an Ethernet passive optical network (EPON) and an optical network unit (ONU) of the EPON. The OLT includes a frame allocator configured to allocate a plurality of frames to each of a plurality of wavelengths, and a frame outputter configured to output the frames through the wavelengths, in which each of the frames includes a frame sequence number corresponding to a sequence order of each frame. The ONU includes a frame receiver configured to receive a plurality of frames each including a frame sequence number and a frame arranger configured to arrange the frames in order based on the frame sequence number.

Abstract: Provided are an Optical Network Unit (ONU) for low latency packet transmission in a Time Division Multiplexing-Passive Optical Network (TDM-PON), a method of operating the ONU, and an apparatus for controlling the ONU. The method includes: receiving, from a base station, first bandwidth allocation information regarding a bandwidth allocated by the base station to a terminal for uplink packet transmission; and transmitting a bandwidth allocation request, which is based on the received first bandwidth allocation information, to an Optical Line Terminal (OLT) before completing packet reception from the base station.

Abstract: A method of registering or de-registering, by an optical line terminal (OLT), one or more optical network units (ONUs) in an optical communications network. The method may include: setting one or more sub-channels for registration or de-registration among two or more sub-channels, and a size of a contention window in the one or more sub-channels; transmitting, to one or more ONUs, a registration information message including information of the one or more set sub-channels and the size of the contention window; receiving, through one of the set sub-channels, a registration or de-registration request message from the one or more ONUs, which receive the registration information message; and registering and de-registering the one or more ONUs.

Abstract: A method of tuning a wavelength in a TWDM-PON which has a plurality of operable channels is provided. First, a second channel is added as an operating channel of the TWDM-PON in which at least a first channel is working, and then an OLT that is providing a service to an ONU through the first channel requests the ONU to tune to the second channel. In response to receiving the request, the ONU determines whether a downstream wavelength of the second channel has been recorded thereon. According to the determination result, the ONU sends to the OLT an ACK message that indicates that the ONU is able to perform wavelength tuning and then commences wavelength tuning to the second channel, or the ONU sends to the OLT a NACK message that indicates that the ONU is unable to perform wavelength tuning.

Abstract: A method of registering or de-registering, by an optical line terminal (OLT), one or more optical network units (ONUs) in an optical communications network. The method may include: setting one or more sub-channels for registration or de-registration among two or more sub-channels, and a size of a contention window in the one or more sub-channels; transmitting, to one or more ONUs, a registration information message including information of the one or more set sub-channels and the size of the contention window; receiving, through one of the set sub-channels, a registration or de-registration request message from the one or more ONUs, which receive the registration information message; and registering and de-registering the one or more ONUs.

Abstract: Provided are an Optical Network Unit (ONU) for low latency packet transmission in a Time Division Multiplexing-Passive Optical Network (TDM-PON), a method of operating the ONU, and an apparatus for controlling the ONU. The method includes: receiving, from a base station, first bandwidth allocation information regarding a bandwidth allocated by the base station to a terminal for uplink packet transmission; and transmitting a bandwidth allocation request, which is based on the received first bandwidth allocation information, to an Optical Line Terminal (OLT) before completing packet reception from the base station.

Abstract: A controlling method for mitigating a rogue behavior of an Optical Network Unit (ONU) having a wavelength-tunable function in a hybrid Passive Optical Network (PON) system. The controlling method includes determining whether a first wavelength for an upstream signal received from the ONU strays away from an allowable range for a second wavelength assigned to the ONU, and, in response to a determination that the first wavelength strays away from the allowable range for the second wavelength, transmitting an upstream wavelength adjustment request message to the ONU to adjust a wavelength for the upstream signal. At this point, a determination on whether the first wavelength strays away from the allowable range for the second wavelength is made by calculating wavelength drift of the first wavelength and determining whether the calculated wavelength drift is greater than a drift threshold.

Abstract: A method for transmitting an orthogonal frequency division multiplexing (OFDM) signal in an optical network and apparatus therefor are provided. The method includes: converting a media access control (MAC) frame into an OFDM frame that contains a physical (PHY) level preamble, using the MAC frame which is transmitted from a MAC layer in a passive optical network (PON) to a PHY layer in an OFDM-PON; and transmitting the generated OFDM frame.

Abstract: There are provided a method of allocating upstream bandwidth resources and a method of transmitting upstream data in an orthogonal frequency division multiple access-open optical subscriber network. The method of allocating an upstream bandwidth resource according to an embodiment of the invention includes receiving queue status information from each optical network unit (ONU), and allocating an upstream bandwidth by providing to each ONU a 2-D upstream bandwidth map on a subcarrier-time resource through a frame synchronized at constant cycles, based on the queue status information received from each ONU.

Abstract: A method of tuning a wavelength in a TWDM-PON which has a plurality of operable channels is provided. First, a second channel is added as an operating channel of the TWDM-PON in which at least a first channel is working, and then an OLT that is providing a service to an ONU through the first channel requests the ONU to tune to the second channel. In response to receiving the request, the ONU determines whether a downstream wavelength of the second channel has been recorded thereon. According to the determination result, the ONU sends to the OLT an ACK message that indicates that the ONU is able to perform wavelength tuning and then commences wavelength tuning to the second channel, or the ONU sends to the OLT a NACK message that indicates that the ONU is unable to perform wavelength tuning.

Abstract: A method of tuning a wavelength of a tunable ONU in a TWDM-PON is provided. The method includes transmitting a wavelength change request message from a source OLT to request the ONU to change a wavelength thereof from a first wavelength to a second wavelength and in response to the wavelength change request message, transmitting a wavelength change response message from the ONU to the source OLT to indicate whether or not the ONU can change a wavelength thereof. The wavelength change request message is ID information for specifying an ONU that is requested to change a wavelength thereof, and the message may comprise one of the following: system ONU ID, channel ONU ID, and individual ONU ID.

Abstract: Provided is a method of selecting a wavelength of an optical network unit including selecting a pre-loaded default wavelength as an available wavelength candidate or the wavelength that has been changed when a preset wavelength changing condition is satisfied as the available wavelength candidate, acquiring frame synchronization for a downstream signal having the same wavelength as the selected available wavelength candidate, and transmitting a registration request message to an optical line terminal (OLT) from which the downstream signal has been transmitted when the frame synchronization is acquired, assigning the available wavelength candidate to an available wavelength used for communication with the OLT and registering the terminal in the OLT when a registration allowance message is received from the OLT.

Abstract: An orthogonal frequency division multiple access-passive optical network including a plurality of optical network units each configured to generate orthogonal frequency division multiplexed signals, which are allocated thereto, based on a central frequency for frequency division multiplexing that is allocated in advance, and to use the generated signals in upstream transmission.

Abstract: Provided is an optical transmission apparatus and method for uplink transmission in an orthogonal frequency division multiple access-passive optical network (OFDMA-PON), wherein the optical transmission apparatus includes a digital signal processor to output a baseband orthogonal frequency division multiplexing (OFDM) signal, a tone generator to generate a dithering tone, a synthesizer to synthesize the dithering tone and the baseband OFDM signal, and an optical source to output an output light in which a spectrum width is increased to be greater than a spectrum width of a carrier light based on the baseband OFMD signal synthesized with the dithering tone.

Abstract: A software-defined networking (SDN) method. The SDN method according to an exemplary embodiment may be used in managing and operating SDN-based network resources in an optical communications network, a fixed mobile convergence subscriber network, a wired broadband subscriber network, a distributed mobile communications base station network, etc.

Abstract: A method for measuring a wavelength channel tuning time by using an optical filter that converts a change of an output wavelength of a tunable device into an optical intensity change, and a system thereof. The system for measuring a wavelength channel tuning time includes: an optical filter set configured to convert a wavelength change of an optical tunable device into an optical output intensity change; at least one or more optical electric converters configured to convert the optical output intensity change output by the optical filter set into an electric signal; and a controller configured to generate a wavelength change command applied to the tunable device, so as to calculate a wavelength channel tuning time of the tunable device by using the wavelength change command and the electric signal output by the optical electric converter.

Abstract: A detachable optical transceiver includes an optical part configured to convert an electric signal into an optical signal and transmit the optical signal, or to convert an optical signal into an electric signal and output the electric signal; and an electronic circuit part configured to amplify an electric signal input from a host board and output the amplified electric signal to the optical part, and to amplify an electric signal output from the optical part and output the amplified electric signal to the host board, wherein the optical part and the electronic circuit part are formed to have housings and the optical part and the electronic circuit part are connected and disconnected via connectors formed on the respective housings.