Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Hiroaki Mukai

Masaki Tanaka

Seiji Kozaki

Toshikazu Yoshida

Yoshihiro Asashiba

Daisuke Ito

Tetsuya Yokotani

Takashi Nishitani

Michiya Takemoto

Yukio Hirano

Koshi Sugimura

Takashi Kikuzawa

Kaori Mie

Kenichi Nakura

Hiroshi Ichibangase

Ryusuke Kawate

Yoshifumi Hotta

Fumihiko Tano

Ken Murakami

Eiichi Horiuchi

Mitsuyoshi Iwasaki

Mitsuru Tsuchida

An ONU receiving an optical signal from an OLT including PON controllers includes: an optical receiver to convert, into an electric signal, an optical signal having a single optical wavelength set out of plural optical wavelengths; and a control frame extractor to extract and hold wavelength correspondence information indicating correspondence between MAC addresses of the PON controllers received from the OLT and the optical wavelengths. The control frame extractor, when receiving a wavelength switching request, extracts the optical wavelength after wavelength switching instructed in the wavelength switching request, obtains a setting address of the MAC address of the PON controller to which the ONU itself should be connected after the wavelength switching based on the extracted optical wavelength after the wavelength switching and the wavelength correspondence information, and determines whether a malfunction occurs based on a transmission source MAC address stored in a received control frame and the setting address.

Slave station device, master station device, optical communication system, and malfunction detection method

An ONU communicates with an OLT that can transmit optical signals having different wavelengths simultaneously and receive optical signals having different wavelengths simultaneously. The ONU includes: an optical transceiver that receives any one of the optical signals that the OLT can transmit and transmits any one of the optical signals that the OLT can receive; a communication failure detection unit that detects a communication failure between the OLT and the ONU; and a wavelength selection unit that, when the communication failure detection unit detects a communication failure, changes a setting of a downstream wavelength to be received by the optical transceiver and an upstream wavelength to be transmitted by the optical transceiver.

Slave station apparatus, master station apparatus, control device, communication system, and wavelength switching method

A communication system in which a master station device is connected to a plurality of slave station devices by an optical transmission line and a plurality of wavelengths are used to perform at least one of downstream communication and upstream communication. The master station device includes: a control unit that assigns a wavelength to be used in communication to the slave station device, and that generates a control signal for notifying the slave station device of the assigned wavelength; and an optical transmitter that transmits the control signal generated by the control unit to the slave station device. The slave station device includes an optical receiver and an optical transmitter that carry out communication with the master station device using the wavelength based on the control signal received from the master station device.

Communication system, master station device, slave station device, control unit, and communication control method

A communication method of an optical communication system in which a user-side optical-line terminal apparatus (ONU) is connected to a station-side optical-line terminal apparatus (OLT) by an optical fiber includes allocating by the OLT to the ONY a transmission bandwidth for transmitting a response signal in a tentative wake-up period in a sleep mode in which a transmission function of the ONU is activated in the tentative wake-up period and deactivated in a sleep period. The method also includes transmitting a transmission bandwidth notification to the ONU, and transmitting, to the ONU, a notification of the sleep period in which deactivation of the transmission function is allowed.

Communication method, optical communication system, station-side optical-line terminal apparatus, and user-side optical-line terminal apparatus

An OLT includes an OLT control unit that generates a control signal for controlling a power saving operation of an ONU by specifying a different idle period with respect to a first power saving operation in which an optical receiver is operated while an optical transmitter of the ONU is controlled to a power saving state and a second power saving operation for controlling the optical transmitter and the optical receiver to the power saving state, and a station-side transmitter that transmits the control signal generated by the OLT control unit to the ONU. The ONU includes an ONU control unit that receives the control signal via the optical receiver to selectively perform the first power saving operation and the second power saving operation based on the idle period specified by the control signal.

Communication system, station-side communication device, user-side communication device, communication method, and control device

An optical communication system that connects a plurality of user-side optical line terminating apparatuses (hereinafter referred to as ONUs) to a station-side optical line terminating apparatus (hereinafter referred to as OLT) using a common optical fiber, wherein the ONU as at least a part of the ONUs includes a transceiver having a power saving function for inactivating a transmitting unit while supplying electric power to a receiving unit and a control apparatus that transmits support information of the power saving function to the OLT via the transceiver, and the OLT includes a control apparatus that generates transmission allowance information of upstream communication based on the support information of the power saving function and a transceiver that receives the support information of the power saving function and transmits the transmission allowance information to the ONU.

Communication system, station-side optical line terminating apparatus, user-side optical line terminating apparatus, control apparatus, and communication method

In a PON system, an ONU includes a receive buffer that stores therein a signal in a downstream direction transmitted from an OLT and a PON control unit that controls transition to a power-saving state and transition to a normal state for the reception buffer. The OLT includes a transmission buffer that stores transmission data to be transmitted to the ONU and the PON control unit that transmits the downstream power-saving-state transition request that requests the ONU to transition to the downstream power-saving state when it is determined that transmission data addressed to the ONU is not present in the transmission buffer. The PON control unit sets the reception buffer to a power-saving state for a predetermined downstream sleep time requested based on the downstream power-saving-state transition request.

PON system, subscriber-side terminal apparatus, station-side terminal apparatus, and power saving method

An ONU includes a power-interruption detecting unit configured to detect power interruption of the ONU, a transmitting and receiving unit capable of being set in a power saving state, and a PON-side control unit configured to notify an OLT of, as power saving return information, a power holding time during occurrence of the power interruption of the ONU and a startup time, which is time until the transmitting and receiving unit returns from the power saving state, and, when the power-interruption detecting unit detects the power interruption, transmit a power interruption notification to the OLT. The OLT includes the PON control unit configured to determine, based on the power saving return information, whether the ONU can transmit the power interruption notification when the power interruption occurs in the power saving state.

Communication system, optical network unit, optical line terminal, control device, and communication control method

An optical communication system connects a plurality of user-side optical line terminating apparatuses (hereinafter referred to as ONUs) to a station-side optical line terminating apparatus (hereinafter referred to as OLT) using a common optical fiber. At least a part of the ONUs includes a transceiver having a power saving function for inactivating a transmitting unit while supplying electric power to a receiving unit and a control apparatus that transmits support information of the power saving function to the OLT via the transceiver, and the OLT includes a control apparatus that generates transmission allowance information of upstream communication based on the support information of the power saving function and a transceiver that receives the support information of the power saving function and transmits the transmission allowance information to the ONU.

In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines. The user-side line terminal apparatus shifting to a holdover state for suppressing a shift to the deregistered state due to occurrence of the time stamp drift error during monitoring in a holdover period set in advance even if line abnormality is detected.

Communication line switching method, communication apparatus, station-side communication apparatus, communication system, and control unit

A communication device operating as a master unit includes: a MAC layer termination functioning unit for extracting, from a receiving signal, queue length information scheduled to be transmitted from an ONU, and controlling transmission of a grant to the ONU; a traffic monitor for measuring an amount of uplink traffic of each ONU; and a bandwidth allocation functioning unit for determining a bandwidth to be allocated to each ONU based on the queue length information extracted by the MAC layer termination functioning unit, the amount of traffic measured by the traffic monitor, and a bandwidth that can be allocated in one cycle of bandwidth update, and issuing a grant according to the determination. The bandwidth allocation functioning unit updates a bandwidth to be allocated periodically.

Communication device, communication system, and method of allocating bandwidth

A communication method of an optical communication system in which a plurality of ONUs are connected to an OLT, includes steps (a) allocating, by the OLT, a transmission bandwidth to an ONU capable of an operation in a sleep mode in which an optical transmitter is tentatively halted for a predetermined sleep period, and transmitting a transmission bandwidth notification to the ONU when the ONU is in the sleep mode and when the ONU is not in the sleep mode; (b) receiving, from the ONU to which the transmission bandwidth is allocated, a response signal when the ONU is not in the sleep mode, wherein the response signal is or is not received during the sleep mode; and (c) suppressing, by the OLT, an alarm in the sleep mode, the alarm being caused by a communication failure with the ONU on a basis of the response signal not being received.

An optical line terminal performs transmission to optical network units using a light signal having a wavelength different for each of systems, allocates communication time to data, which is transmitted from the optical network units, in a time division manner for each of the systems, selects, for each of the optical network units, a system for performing data transmission, and transmits the data using a wavelength corresponding to the selected system. The optical network unit includes: ith blocking filter that removes a component other than a component in a predetermined wavelength band, which is set to correspond to an ith system, from a received light signal; and ith PON processing unit that applies termination processing to signals and transmitting the data based on an allocation result of the optical line terminal. The PON system includes n optical network units corresponding to i=1 to i=n.

PON system and redundancy method

The control device includes a power-saving control unit that intermittently repeats, based on a power saving permission signal transmitted from the master station apparatus, power saving control in which the slave station stops or reduces power supply to a transmitter or a receiver for a predetermined pause duration while maintaining a communication link and a monitoring unit that monitors out of synchronization by comparing a synchronization signal received from the OLT and a time of the ONU. The control device shifts from a registered state to a deregistered state when the monitoring unit detects the out of synchronization. On the other hand, after the pause duration of the power saving control, the control device suppresses the shift to the deregistered state due to the detection of the out of synchronization.

Communication method for optical communication system, optical communication system, slave station apparatus, control device, and computer program

A communication control method performing Discovery processing, which is a procedure at an OLT to detect an ONU newly connected, in a PON system, the method includes: a transmission-permission-signal transmitting step of transmitting, by the OLT, a transmission permission signal for discovery, which includes an individual number of an ONU that is permitted to respond and mask information for designating a match-detection target bit for the individual number; and a registration-request-signal transmitting step of comparing, by an ONU, which is not registered in the OLT, a match-detection target bit for the individual number designated in the mask information with an individual number of the ONU based on a received transmission permission signal, and when the target bit and the individual number match each other, transmitting a registration request signal to the OLT.

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Tokyo, Japan

Hiroaki Mukai