Hitachi, Ltd.

Hitachi Astemo Ltd.

Jun Sugawa

Hiroki Ikeda

Toshiyuki Odaka

Tohru Kazawa

Hidehiro Toyoda

Daisuke Mashimo

Kenichi Osada

Kazuyoshi Serizawa

Masayuki Takase

Taisuke Ueta

Masayoshi Yagyu

Yasunari Shinohara

Shuhei Kaneko

Masahito Takei

An in-vehicle network system which is mounted on a vehicle includes an electronic control unit, a plurality of gateway devices, and a plurality of sensor devices that collects ambient information which is information around the vehicle. Each of the sensor devices communicates with the electronic control unit via at least one gateway device. The electronic control unit includes a mode management unit that determines one operation mode in a plurality of operation modes associated with the sensor device to be operated, and a sleep instruction control unit that specifies a gateway device which is the gateway device, in which the connected sensor device does not operate, and does not need to relay sensor information, based on the operation mode determined by the mode management unit, and transitions the gateway device having no need to relay the sensor information to a low power state in which a processing capacity is lowered.

In-vehicle network system, electronic control unit, and gateway device

To enable a communication apparatus, which transmits and receives data with a partially reconfigurable logic circuit, to configure a module while continuing a communication process. A communication apparatus transmits and receives data and includes a partially reconfigurable logic circuit and a management unit for managing a circuit configuration of the logic circuit. The logic circuit includes a plurality of modules and a data distribution unit. The management unit fixedly arranges a plurality of coupling interfaces, which are used for sending data to a module determined as a distribution destination of data by the data distribution unit and which are respectively linkable to the plurality of modules, at prescribed positions on the logic circuit, and creates the module in the partially reconfigurable area of the logic circuit so as to be linked to any of the plurality of coupling interfaces.

Communication apparatus, communication system, and circuit configuration control method

Provided is a station-side apparatus configured to conduct optical communication with a plurality of subscriber apparatuses via a plurality of wavelengths. The station-side apparatus includes a storage apparatus, management information stored in the storage apparatus and configured to indicate whether or not a subscriber apparatus is a first apparatus whose wavelength used for communication is changed to another wavelength, and a transmission unit configured to transmit downlink frames addressed to the plurality of subscriber apparatuses in an order of transmission determined based on the management information.

Station-side apparatus and communication method

Provided is a network system including a subscriber apparatus and a station-side apparatus connected with the subscriber apparatus via an optical line. The subscriber apparatus includes a transceiver for receiving an instruction to change wavelengths for signals to be sent and received, receiving a downstream signal sent from the station-side apparatus and having a wavelength designated by the instruction, and sending an upstream signal having a wavelength designated by the instruction to the station-side apparatus. The subscriber apparatus includes a controller for identifying at least one property of the received downstream signal and determining wavelengths for signals to be sent and received based on the identified at least one property.

Network system

In a PON system in which plural kinds of modulation schemes coexist, when uplink burst signals from respective ONUs are received, the receiving efficiency degrades as the number of the times of switching of the modulation scheme increases. In an optical access (PON) system supporting plural kinds of modulation schemes, an OLT allocates bandwidths for uplink signals, i.e., transmission timings each including a transmission start time and a transmission duration, to ONUs, respectively, such that the bandwidths allocated to plural ONUs for the same modulation scheme are as successive as possible. Based on the transmission timings allocated to the respective ONUs, the OLT switches the modulation scheme of a modulation-scheme variable burst-mode optical transmitter/receiver by control of a modulation scheme controller.

Dynamic bandwidth allocation method, OLT, and PON system

An aspect of this invention is a network system including subscriber apparatuses and a station-side apparatus for communicating with the subscriber apparatuses. The station-side apparatus communicates with the subscriber apparatuses using wavelengths. The station-side apparatus determines a wavelength to be used by each of at least one subscriber apparatus of the subscriber apparatuses based on effective transmission rates used by the subscriber apparatuses in communications with the station-side apparatus.

Network system, station-side apparatus, and method of controlling communications

Technology to provide linked control of bandwidth allocation to a plurality of optical network units among the plural wavelengths by a bandwidth allocation section coupled to the plural optical network units.

Optical line terminal and optical network system

To, even when a transmission wavelength varies in each ONU and an optical amplifier gain depends on the wavelength in an OLT equipped with an optical amplifier, prevent the optical amplifier gain from varying in every ONU and thus prevent deterioration of a dynamic range. The OLT estimates a transmission wavelength of each ONU at the time of ONU registration, and retains a correspondence between an ONU identifier and the transmission wavelength. Moreover, for every burst, an injection current to the optical amplifier is adjusted based on a wavelength and optical amplifier characteristic database.

Burst-mode receiver equipped with optical amplifier, method for controlling optical amplifier, and system

There is a need to recover an ONU from a sleep state for communication with the PON before a specified sleep cancel time in a short period of time without degrading the band use efficiency. An OLT manages an electric state of each ONU connected to a PON. When at least one ONU is in sleep mode, the OLT transmits a grant to allocate a band for a sleep cancel report to the ONU. When the sleep-mode ONU requires communication, the ONU transmits the sleep cancel report to the OLT using the band for the sleep cancel report. When receiving the sleep cancel report, the OLT changes the managed ONU to a normal state and resumes the communication with the PON.

Method of recovery from sleep state of an ONU in a PON system capable of power saving

There is a need to provide a multirate burst mode receiver for an OLT to be capable of receiving a high-speed burst signal without the need for a special capability of an ONU in a PON system including a mix of ONUs at different transmission bit rates. A multirate burst mode receiver according to the invention includes a signal input discrimination section and a bit rate discrimination section. The signal input discrimination section detects an average amplitude to discriminate signal input. The bit rate discrimination section detects an envelope curve for a high-frequency component to discriminate a signal bit rate. Based on a discrimination result from the signal input discrimination section and the bit rate discrimination section, the multirate burst mode receiver switches a setting for an optical signal reception section and a serial-parallel converter corresponding to the reception bit rate.

Multirate burst mode receiver

A burst mode receiver including a CDR circuit that does not perform bit synchronization determination at a wrong position even when a burst signal waveform containing a distortion is input is provided. The burst mode receiver includes a CDR circuit for reproducing clock and data from a received signal, a bit synchronization determination circuit for determining whether the CDR circuit is in an optimum phase, a waveform distortion determination circuit for determining from the received signal whether there is waveform distortion, and a CDR output enable determination circuit for determining whether an output of the CDR circuit is valid or invalid. The CDR output enable determination circuit performs CDR output enable determination based on a bit synchronization determination result and a waveform distortion determination result.

Growing community of inventors

Kamakura, Japan

Jun Sugawa