Patents by Inventor Daisuke MASUNAGA

Daisuke MASUNAGA 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: 10020887
    Abstract: A wireless communication system includes a baseband processing device configured to transmit a data signal via an optical transmission line, and a wireless device configured to receive the data signal via the optical transmission line and carry out wireless transmission of an output signal obtained by amplifying the data signal, wherein the wireless device is configured to amplify the data signal to generate the output signal, generate a feedback signal according to the output signal, and transmit the feedback signal to the baseband processing device via the optical transmission line, and wherein the baseband processing device is configured to acquire the feedback signal from the wireless device, and execute first processing of multiplying the data signal by a distortion compensation coefficient corresponding to an inverse characteristic of distortion in the radio frequency circuit based on the feedback signal.
    Type: Grant
    Filed: January 27, 2017
    Date of Patent: July 10, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Daisuke Masunaga, Akira Toyomane, Katsutoshi Usami, Masaaki Okada
  • Publication number: 20170302229
    Abstract: An amplification device includes a first amplifier configured to amplify an input signal in accordance with a first gate voltage, and a second amplifier configured to amplify the input signal in accordance with a second gate voltage, wherein at least one of the first gate voltage and the second gate voltage are controlled on the basis of a current ratio of a first drain current of the first amplifier to a second drain current of the second amplifier.
    Type: Application
    Filed: March 20, 2017
    Publication date: October 19, 2017
    Applicant: FUJITSU LIMITED
    Inventors: Takumi Takayashiki, Tatsuhiko Tajima, Daisuke Masunaga
  • Publication number: 20170141850
    Abstract: A wireless communication system includes a baseband processing device configured to transmit a data signal via an optical transmission line, and a wireless device configured to receive the data signal via the optical transmission line and carry out wireless transmission of an output signal obtained by amplifying the data signal, wherein the wireless device is configured to amplify the data signal to generate the output signal, generate a feedback signal according to the output signal, and transmit the feedback signal to the baseband processing device via the optical transmission line, and wherein the baseband processing device is configured to acquire the feedback signal from the wireless device, and execute first processing of multiplying the data signal by a distortion compensation coefficient corresponding to an inverse characteristic of distortion in the radio frequency circuit based on the feedback signal.
    Type: Application
    Filed: January 27, 2017
    Publication date: May 18, 2017
    Inventors: Daisuke MASUNAGA, Akira TOYOMANE, Katsutoshi USAMI, Masaaki OKADA
  • Publication number: 20160112134
    Abstract: A wireless communication system includes a baseband processing device configured to transmit a data signal via an optical transmission line, and a wireless device configured to receive the data signal via the optical transmission line and carry out wireless transmission of an output signal obtained by amplifying the data signal, wherein the wireless device is configured to amplify the data signal to generate the output signal, generate a feedback signal according to the output signal, and transmit the feedback signal to the baseband processing device via the optical transmission line, and wherein the baseband processing device is configured to acquire the feedback signal from the wireless device, and execute first processing of multiplying the data signal by a distortion compensation coefficient corresponding to an inverse characteristic of distortion in the radio frequency circuit based on the feedback signal.
    Type: Application
    Filed: August 14, 2015
    Publication date: April 21, 2016
    Inventors: Daisuke MASUNAGA, Akira TOYOMANE, Katsutoshi USAMI, Masaaki OKADA
  • Patent number: 8897391
    Abstract: A distortion compensator compensates for distortion of a signal caused by an amplifier. A storage section stores a plurality of compensation coefficients used for distortion compensation. A selection section selects a compensation coefficient corresponding to an index value indicative of a power level of the signal from among the plurality of compensation coefficients. The selection section determines whether or not the power level is higher than a threshold, and uses, based on a determination result, a first index value calculated without using a logarithmic operation or a second index value calculated by using a logarithmic operation.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: November 25, 2014
    Assignee: Fujitsu Limited
    Inventors: Daisuke Masunaga, Satoshi Matsubara, Takeshi Ohba, Hideharu Shako
  • Publication number: 20130083866
    Abstract: A distortion compensator compensates for distortion of a signal caused by an amplifier. A storage section stores a plurality of compensation coefficients used for distortion compensation. A selection section selects a compensation coefficient corresponding to an index value indicative of a power level of the signal from among the plurality of compensation coefficients. The selection section determines whether or not the power level is higher than a threshold, and uses, based on a determination result, a first index value calculated without using a logarithmic operation or a second index value calculated by using a logarithmic operation.
    Type: Application
    Filed: September 12, 2012
    Publication date: April 4, 2013
    Applicant: FUJITSU LIMITED
    Inventors: Daisuke MASUNAGA, Satoshi MATSUBARA, Takeshi OHBA, Hideharu SHAKO