Patents by Inventor Taizo Maeda

Taizo Maeda has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11196485
    Abstract: A network system includes a first device and a second device coupled to the first device. The second device configured to calculate a bandwidth of an optical signal narrowed by a wavelength filter from the number of wavelength filters on a transmission route of the optical signal, to select, based on a plurality of combinations of a degree of multilevel and the baud rate, and a correspondence between a lower limit value of a bandwidth of the optical signal and a lower limit value of an optical signal to noise ratio (OSNR) for maintaining predetermined quality of the optical signal, one or more first combinations from the plurality of combinations, to select a second combination from the one or more first combinations, and to set the degree of multilevel and the baud rate of the second combination in the first device.
    Type: Grant
    Filed: September 1, 2020
    Date of Patent: December 7, 2021
    Assignee: FUJITSU LIMITED
    Inventors: Taizo Maeda, Kosuke Komaki
  • Publication number: 20210075506
    Abstract: A network system includes a first device and a second device coupled to the first device. The second device configured to calculate a bandwidth of an optical signal narrowed by a wavelength filter from the number of wavelength filters on a transmission route of the optical signal, to select, based on a plurality of combinations of a degree of multilevel and the baud rate, and a correspondence between a lower limit value of a bandwidth of the optical signal and a lower limit value of an optical signal to noise ratio (OSNR) for maintaining predetermined quality of the optical signal, one or more first combinations from the plurality of combinations, to select a second combination from the one or more first combinations, and to set the degree of multilevel and the baud rate of the second combination in the first device.
    Type: Application
    Filed: September 1, 2020
    Publication date: March 11, 2021
    Applicant: FUJITSU LIMITED
    Inventors: Taizo MAEDA, Kosuke Komaki
  • Patent number: 10715363
    Abstract: An optical communication apparatus has an interface circuit that acquires transfer condition information including a bit rate and a channel spacing of an optical network, a processor that selects a modulation scheme in accordance with the transfer condition information and operates in the modulation scheme, wherein the processor is configured to select a first modulation scheme when the bit rate is greater than a first value in accordance with the channel spacing, and select a second modulation scheme when the bit rate is smaller than the first value, the second modulation scheme having a data transfer performance higher than the first modulation scheme.
    Type: Grant
    Filed: September 3, 2019
    Date of Patent: July 14, 2020
    Assignee: FUJITSU LIMITED
    Inventors: Naoya Okada, Taizo Maeda, Kosuke Komaki
  • Patent number: 10707963
    Abstract: A network design method includes calculating, from the number of wavelength filters on a transmission route of an optical signal, a bandwidth of the optical signal after narrowing by the wavelength filters, selecting, from a plurality of combinations of a multi-level modulation system and a baud rate about the optical signal set in a transmitting apparatus, one or more first combinations about which a lower-limit value of the bandwidth of the optical signal in each of the combinations is equal to or smaller than the bandwidth of the optical signal after narrowing, and selecting a second combination from the one or more first combinations based on a minimum value of an OSRN of the optical signal in the selected combinations.
    Type: Grant
    Filed: March 5, 2019
    Date of Patent: July 7, 2020
    Assignee: FUJITSU LIMITED
    Inventor: Taizo Maeda
  • Publication number: 20200213009
    Abstract: An optical communication apparatus includes an interface circuit that acquires bit rate information of an optical network, and a processor that selects a modulation scheme in accordance with the bit rate information and operates in the modulation scheme, wherein the processor is configured to select a first modulation scheme when the bit rate is equal to or greater than a first value, and select a second modulation scheme when the bit rate is smaller than the first value, the second modulation scheme having a data transfer performance higher than the first modulation scheme.
    Type: Application
    Filed: December 10, 2019
    Publication date: July 2, 2020
    Applicant: FUJITSU LIMITED
    Inventors: Naoya OKADA, Taizo MAEDA, Kosuke Komaki
  • Patent number: 10541757
    Abstract: A receiving apparatus includes a first processor configured to compensate, in a perturbation back-propagation (PBP) scheme, waveform degradation of an optical signal by traveling an optical transmission line due to a nonlinear optical effect; a memory; and a second processor coupled to the memory and the second processor configured to change a gamma coefficient to be used in the PBP scheme, measure reception quality of the optical signal for each of gamma coefficients obtained by the changing, specify a gamma coefficient in accordance with the reception quality from among the gamma coefficients obtained by the changing, and set the specified gamma coefficient as a parameter of the PBP scheme.
    Type: Grant
    Filed: May 18, 2017
    Date of Patent: January 21, 2020
    Assignee: FUJITSU LIMITED
    Inventor: Taizo Maeda
  • Publication number: 20190288775
    Abstract: A network design method includes calculating, from the number of wavelength filters on a transmission route of an optical signal, a bandwidth of the optical signal after narrowing by the wavelength filters, selecting, from a plurality of combinations of a multi-level modulation system and a baud rate about the optical signal set in a transmitting apparatus, one or more first combinations about which a lower-limit value of the bandwidth of the optical signal in each of the combinations is equal to or smaller than the bandwidth of the optical signal after narrowing, and selecting a second combination from the one or more first combinations based on a minimum value of an OSRN of the optical signal in the selected combinations.
    Type: Application
    Filed: March 5, 2019
    Publication date: September 19, 2019
    Applicant: FUJITSU LIMITED
    Inventor: Taizo MAEDA
  • Publication number: 20180212685
    Abstract: A receiving apparatus includes a first processor configured to compensate, in a perturbation back-propagation (PBP) scheme, waveform degradation of an optical signal by traveling an optical transmission line due to a nonlinear optical effect; a memory; and a second processor coupled to the memory and the second processor configured to change a gamma coefficient to be used in the PBP scheme, measure reception quality of the optical signal for each of gamma coefficients obtained by the changing, specify a gamma coefficient in accordance with the reception quality from among the gamma coefficients obtained by the changing, and set the specified gamma coefficient as a parameter of the PBP scheme.
    Type: Application
    Filed: March 26, 2018
    Publication date: July 26, 2018
    Applicant: FUJITSU LIMITED
    Inventor: Taizo MAEDA
  • Publication number: 20170366274
    Abstract: A receiving apparatus includes a first processor configured to compensate, in a perturbation back-propagation (PBP) scheme, waveform degradation of an optical signal by traveling an optical transmission line due to a nonlinear optical effect; a memory; and a second processor coupled to the memory and the second processor configured to change a gamma coefficient to be used in the PBP scheme, measure reception quality of the optical signal for each of gamma coefficients obtained by the changing, specify a gamma coefficient in accordance with the reception quality from among the gamma coefficients obtained by the changing, and set the specified gamma coefficient as a parameter of the PBP scheme.
    Type: Application
    Filed: May 18, 2017
    Publication date: December 21, 2017
    Applicant: FUJITSU LIMITED
    Inventor: Taizo MAEDA
  • Publication number: 20170359085
    Abstract: A coding apparatus includes a check matrix, a calculator, a selector, and a synthesizer. The check matrix includes a parity operation matrix including a matrix along a diagonal, a circulant matrix positioned one row and a predetermined number of rows below the diagonal, and an information operation matrix. The calculator sets, in response to an input of a bit sequence of a message, every pattern of initial values to a less-significant bit sequence of parity bits corresponding to the number of the predetermined rows, and calculates parity bit sequences for the respective patterns of the initial values. The selector selects a parity bit sequence corresponding to one of the patterns of initial values when the less-significant bit sequence of the parity bit sequence matches the pattern of initial values. The synthesizer concatenates the selected parity bit sequence to the bit sequence of the message, and outputs the resultant code word.
    Type: Application
    Filed: May 26, 2017
    Publication date: December 14, 2017
    Applicants: FUJITSU LIMITED, Mobile Techno Corp.
    Inventors: Taizo MAEDA, Yohei KOGANEl, Masanori YOFUNE, Cong LI
  • Patent number: 9825731
    Abstract: An optical transmission system includes a first optical transmission apparatus that adds a plurality of error correction codes to a main signal, retrieves, from a first error correction code that is added to the main signal and that corresponds to a first sub-carrier among the plurality of sub-carriers, a first code portion in excess of a predetermined redundancy level, distributes the first code portion to a second sub-carrier among the plurality of sub-carriers, concatenates a second code portion into the first error correction code, and transmits an optical signal including the main signal multiplexed with the first error correction code that has been concatenated with the second code portion.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: November 21, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Taizo Maeda, Yohei Koganei, Ichiro Nakajima
  • Publication number: 20160261368
    Abstract: An optical transmission system includes: a first optical transmission apparatus configured to add an error correction code (ECC) having a code length in accordance with transmission quality of each of sub-carriers forming a super channel to a main signal, retrieve, from the ECC added to the main signal on a sub-carrier to be processed, a code portion in excess of a predetermined redundancy level, distribute the code portion to another sub-carrier, and concatenate the code portion of the ECC to be added to a main signal on the another sub-carrier into the ECC added to a main signal on the sub-carrier to be processed; and a second optical transmission apparatus configured to concatenate the cord portion of the ECC distributed from another sub-carrier into the ECC included in the optical signal, and decode a main signal in the optical signal on a corresponding sub-carrier by using the concatenated ECC.
    Type: Application
    Filed: March 1, 2016
    Publication date: September 8, 2016
    Inventors: Taizo MAEDA, Yohei Koganei, ICHIRO NAKAJIMA
  • Patent number: 9419741
    Abstract: An optical transmission system includes: a plurality of optical transmission devices each including: an adjustment unit to adjust optical power of channels in the WDM optical signal; and a controller to control the adjustment unit based on an adjustment amount, and a management device including: a converter to convert an evaluation value for evaluating quality of service provided by using the channels in the WDM optical signal into a threshold value of transmission quality to be satisfied by the channels; and a determination unit to calculate the transmission quality of the channels based on monitoring information of the channels in the WDM optical signal adjusted by the adjusting unit of at least one of the plurality of optical transmission devices and to determine the adjustment amount to be set for the optical transmission device so that the calculated transmission quality of the channels satisfy the threshold value.
    Type: Grant
    Filed: June 25, 2014
    Date of Patent: August 16, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Taizo Maeda, Takuya Miyashita
  • Publication number: 20150016818
    Abstract: An optical transmission system includes: a plurality of optical transmission devices each including: an adjustment unit to adjust optical power of channels in the WDM optical signal; and a controller to control the adjustment unit based on an adjustment amount, and a management device including: a converter to convert an evaluation value for evaluating quality of service provided by using the channels in the WDM optical signal into a threshold value of transmission quality to be satisfied by the channels; and a determination unit to calculate the transmission quality of the channels based on monitoring information of the channels in the WDM optical signal adjusted by the adjusting unit of at least one of the plurality of optical transmission devices and to determine the adjustment amount to be set for the optical transmission device so that the calculated transmission quality of the channels satisfy the threshold value.
    Type: Application
    Filed: June 25, 2014
    Publication date: January 15, 2015
    Applicant: FUJITSU LIMITED
    Inventors: Taizo MAEDA, Takuya MIYASHITA
  • Patent number: 8891961
    Abstract: In an optical communication device, a light source is capable of varying the wavelength of light to be output. An optical multiplexer multiplexes light output from the light source with signal light received from a transmission path. To an optical medium, light output from the optical multiplexer is input. A monitor monitors light having a predetermined wavelength output from the optical medium. A wavelength number measuring unit measures the number of wavelengths of signal light transmitted through the transmission path based on the result of monitoring by the monitor.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: November 18, 2014
    Assignee: Fujitsu Limited
    Inventors: Taizo Maeda, Takashi Toyomaki, Takuya Miyashita
  • Patent number: 8611446
    Abstract: A communication system is provided for communicating over a network. A plurality of transmission devices are disposed within a network and connected by transmission channels. A control device calculates initial data required during an initial operation of the transmission devices and sets the initial data to the transmission devices. The transmission devices perform reception processing using maximum likelihood sequence estimation, and the control device obtains, as the initial data, with respect to paths that are signal communication pathways between the transmission devices and in accordance with transmission states of individual paths, initial likelihood information that is initial-stage likelihood information for performing the maximum likelihood sequence estimation.
    Type: Grant
    Filed: November 23, 2009
    Date of Patent: December 17, 2013
    Assignee: Fujitsu Limited
    Inventors: Taizo Maeda, Motoyoshi Sekiya, Takuya Miyashita, Rikiya Watanabe
  • Patent number: 7970286
    Abstract: In a wavelength-division multiplexing communications system including a plurality of optical transmission devices having an optical amplifier, downstream optical transmission devices transmit gain wavelength characteristic information of an optical amplifier in each of the downstream optical transmission devices to an upstream optical transmission device. The upstream optical transmission device controls gain wavelength characteristics on the basis of the received gain wavelength characteristic information.
    Type: Grant
    Filed: August 19, 2009
    Date of Patent: June 28, 2011
    Assignee: Fujitsu Limited
    Inventor: Taizo Maeda
  • Publication number: 20100128809
    Abstract: A communication system is provided for communicating over a network. A plurality of transmission devices are disposed within a network and connected by transmission channels. A control device calculates initial data required during an initial operation of the transmission devices and sets the initial data to the transmission devices. The transmission devices perform reception processing using maximum likelihood sequence estimation, and the control device obtains, as the initial data, with respect to paths that are signal communication pathways between the transmission devices and in accordance with transmission states of individual paths, initial likelihood information that is initial-stage likelihood information for performing the maximum likelihood sequence estimation.
    Type: Application
    Filed: November 23, 2009
    Publication date: May 27, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Taizo Maeda, Motoyoshi Sekiya, Takuya Miyashita, Rikiya Watanabe
  • Publication number: 20100040373
    Abstract: In a wavelength-division multiplexing communications system including a plurality of optical transmission devices having an optical amplifier, downstream optical transmission devices transmit gain wavelength characteristic information of an optical amplifier in each of the downstream optical transmission devices to an upstream optical transmission device. The upstream optical transmission device controls gain wavelength characteristics on the basis of the received gain wavelength characteristic information.
    Type: Application
    Filed: August 19, 2009
    Publication date: February 18, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Taizo MAEDA
  • Patent number: 7619813
    Abstract: A wavelength division multiplexing (WDM) device, an optical leakage prevention method, and a WDM communication system are disclosed. The WDM device includes a level adjusting unit for receiving an optical signal, for adjusting the optical power level of the received optical signal, and for outputting the level-adjusted optical signal; and a controlling unit for analyzing the optical power level of the optical signal output from the level adjusting unit, for controlling the level adjusting unit so that the optical power level of the output optical signal stays at a constant level, and for transitioning to an “off-state” when the optical power level of the output optical signal becomes less than a predetermined disconnection-detection threshold so that the level adjusting unit gives a predetermined attenuation to the input optical signal.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: November 17, 2009
    Assignee: Fujitsu Limited
    Inventors: Taizo Maeda, Satoru Okano, Takehiro Fujita