Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Akihiko Tsuchiya

Yusuke Yajima

Tohru Kazawa

Masaki Ohira

Yoshinobu Morita

Masayuki Takase

Taisuke Ueta

Norihiro Sakamoto

Hayato Hoshihara

Masahiko Mizutani

Masatoshi Takihiro

In an exemplary communication apparatus, an assignment module determines whether processing for a second packet assigned the flow ID associated with a received first packet is being executed. The assignment module determines a parallel processing module to execute processing for the first packet and a parameter to be included in a notice of assignment. The determined parallel processing module acquires a result of execution of the processing for the second packet from the computation table or the result of execution of the processing held in the parallel processing module according to the received notice of assignment. The determined parallel processing module executes the processing for the first packet using the result of execution of the processing for the second packet and the information included in the notice of assignment, and updates a computation table with a result of execution of the processing for the first packet.

Communication apparatus and communication method

A communication device includes a flow identification unit specifying a user corresponding to received data, a bandwidth control unit controlling transmission of the received data so as not to exceed a bandwidth corresponding to the selected communication path in two bandwidths allocated to the specified user, and a label addition unit adding the label value corresponding to the selected communication path to the data received from the bandwidth control unit and transmitting the data. The label addition unit executes, upon detecting a trigger for a change in the selection of the communication path, changing the selection of the label value and transmitting a feedback signal for giving notice of the change in the selection of the communication path to the bandwidth control unit in a given order. The bandwidth control unit executes a process of changing the setup of the bandwidth on the basis of the received feedback signal.

Communication device, method for controlling the communication device, and communication system

Provided is a passive optical network system for operating a mixture of PONs with differing transmission speeds and is capable of reducing power consumption on the basis of the amount of signals being transmitted. The master station of the passive optical network system, which determines the amount and timing of signals sent thereto by each of a plurality of slave stations on the basis of the requests of the plurality of slave stations and receives signals from the plurality of slave stations via an optical fiber network, is equipped with a control unit that determines in each set cycle the amount, transmission timing, and transmission speed of the signals that each slave station is permitted to transmit to said master station on the basis of the amount of signals that each of the plurality of slave stations has requested to transmit, and that notifies such to each slave station. Additionally, each of the plurality of slave stations is equipped with a control unit that transmits signals to the master station at a first transmission speed or a second transmission speed that is faster than the first transmission speed, and is configured to transmit signals with either the first transmission speed or the second transmission speed on the basis of notifications from the master station.

Passive optical network system and operating method thereof

A passive optical network system such that the power consumption can be reduced as much as possible according to the end-user traffic. An OLT uses the DBA function thereof and sequentially uses frequencies in ascending order of transmission rate in order to sequentially allocate bands to ONUs in ascending order of the requested bandwidth. At this time, a frequency to be allocated is selected so that the bandwidth allocated to each ONU is narrower than a maximum bandwidth through which transmission using the allocated wavelength is enabled. An OLT uses a grant area to specify the transmission timing of the secondary station and to inform the specified transmission timing to the secondary station. In addition, an area is set for storing information used to inform the secondary station of a new frequency to be used.

Optical multiplexing terminating device, passive optical network system and method for allocating wavelength

In a light reception element such as an APD (Avalanche Photo Diode) used for receiving a high-speed and weak optical signal, it is possible to prevent the phenomenon of distortion of a signal inputted after a large-level light is received. A PON (Passive Optical Network) system includes an OLT (Optical Line Terminal) which can impartially and effectively transmit light reception data to each ONU (Optical Network Unit). According to a light reception amplitude received by each ONU, an inter-frame gap of an appropriate length is assigned for each ONU. The OLT includes a unit for measuring and accumulating the reception light amplitude and data on the inter-frame gap of an appropriate length decided in advance according to the characteristic of the light reception device and generates a grant value for assuring an inter-frame gap of an appropriate length by using the both information.

Apparatus of adjusting optical signal transmission timing

There are provided multiple candidates for FEC codes selectable for each of the ONTs. An OLT is provided with: means for storing redundancy and a code length of each FEC code in a table; means for selecting an FEC code; means for encoding or decoding data using the selected FEC code; means for calculating a bandwidth in consideration for the FEC redundancy and the code length with reference to the table during band assignment calculation; and means for notifying the destination ONT of the selected FEC code.

Optical access system

In the configuration of an optical communication system interconnecting a parent station and a plurality of child stations via an optical fiber network equipped with an optical splitter, RE is provided having a measuring unit for measuring a transmission distance or time to a child station, a determining unit for determining a timing when a child station transmits a signal, in accordance with a transmission bandwidth request from the child station, and a signal processing unit for processing a signal received from a child station and transmitting the processed signal to the parent station. When a burst signal is received from each child station at the determined timing, a portion of the header of the burst signal is deleted, and a dummy signal is inserted into the deleted area and a gap area between received burst signals to convert the burst signals into a series of signals to be sent to the parent station.

Optical passive network system and its operation method

In a passive optical network system in which communication signals from a master station to a plurality of subsidiary stations are multiplexed by time division and transmitted, after converting (modulating) data with a high transmission speed to a low transmission speed, a base speed, in the master station, a header including an identifier destined for each subsidiary station is attached to the data with a low transmission speed and the converted data, respectively, the data and the header being multiplexed by time division inside a frame and transmitted to the subsidiary stations at the base speed. In the subsidiary station having received the concerned frame, only the data destined for the station itself is read, on the basis of the identifier included in the header, and by means of demodulation, the converted data are reconverted to the original high speed data and supplied to a user terminal.

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Yokohama, Japan

Akihiko Tsuchiya