Patents Assigned to Japan as represented By President Of Hokkaido University
  • Patent number: 7565171
    Abstract: A radio unit (2000) separates a signal from a specific terminal among signals from array antennas (#1-#4) based on a reception weight vector calculated by a reception weight vector calculator (20). A reception response vector calculator (22) derives a reception response vector of a propagation path for the signal from the specific terminal. A transmission response vector estimator (40) regards an estimation result of the reception response vector calculator (22) as a composite waveform of a function of a plurality of frequencies, determined in accordance with a Doppler frequency, and predicts a transmission response vector at a time point of transmission by obtaining coefficients of respective function. A transmission weight vector calculator (30) controls antenna directivity in transmission, based on a prediction result of the transmission response vector estimator (40).
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: July 21, 2009
    Assignees: Sanyo Electric Co., Ltd., Japan as represented by President of Hokkaido University
    Inventors: Yoshiharu Doi, Yasutaka Ogawa, Takeo Ohgane
  • Publication number: 20070058698
    Abstract: When once determined to be free of any demodulation error by an interference removing unit provided user by user, a replica signal calculated by the interference removing unit is subtracted from an input signal vector, and a calculated user signal is output as it is as a final user signal. When it is determined by the interference removing unit that there is a demodulation error, the user signal is again calculated by the interference removing unit of an interference canceller of a next stage. As subtraction of the replica signal corresponding to the user signal having a demodulation error from the input signal vector is inhibited, precision of the interference wave removal can be improved.
    Type: Application
    Filed: November 13, 2006
    Publication date: March 15, 2007
    Applicants: Japan as Represented by President of Hokkaido University, SANYO ELECTRIC CO., LTD.
    Inventors: Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura, Masashi Iwami, Jun Kitakado, Yoshiharu Doi
  • Patent number: 7145942
    Abstract: When once determined to be free of any demodulation error by an interference removing unit provided user by user, a replica signal calculated by the interference removing unit is subtracted from an input signal vector, and a calculated user signal is output as it is as a final user signal. When it is determined by the interference removing unit that there is a demodulation error, the user signal is again calculated by the interference removing unit of an interference canceller of a next stage. As subtraction of the replica signal corresponding to the user signal having a demodulation error from the input signal vector is inhibited, precision of the interference wave removal can be improved.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: December 5, 2006
    Assignees: Japan as represented By President Of Hokkaido University, Sanyo Electric Co., Ltd.
    Inventors: Yasutaka Ogawa, Takeo Ohgane, Toshihiko Nishimura, Masashi Iwami, Jun Kitakado, Yoshiharu Doi
  • Patent number: 6590532
    Abstract: A radio equipment 1000 separates a signal of a specific terminal from signals from adaptive array antennas #1 to #4, based on a reception weight vector calculated by a reception weight vector calculator 20. Reception coefficient vector calculator 22 provides an impulse response of a signal propagation path of the specific terminal. A transmission coefficient vector estimator 32 predicts a propagation path at the time of transmission, from the result of estimation by the reception coefficient vector calculator 22. The transmission weight vector calculator 30 controls, based on the result of prediction by the transmission coefficient vector estimator 32, the antenna directivity at the time of transmission. Thus, degradation of error rate of the down link generated by the time difference between up/down links can be suppressed.
    Type: Grant
    Filed: December 18, 2001
    Date of Patent: July 8, 2003
    Assignees: Japan as represented by President of Hokkaido University, Sanyo Electric Co., Ltd.
    Inventors: Yasutaka Ogawa, Takeo Ohgane, Yoshiharu Doi
  • Patent number: 5798459
    Abstract: The present invention relates to a subject identification method which is adapted for performing an examination as to whether any change exists on an subject, or adapted for performing an estimation of a degree of the change on the subject. It is an aim that the examination and the estimation are performed with great accuracy. Residual signals are evaluated by means of letting an inverse filter interact with a standard and samples which may be out of the standard, so that a plurality of statistical variables are extracted, thereby testing or estimating as to whether a statistical significant difference exists between those two statistical variable groups.
    Type: Grant
    Filed: April 1, 1997
    Date of Patent: August 25, 1998
    Assignees: Japan as represented by President of Hokkaido University, Koa Oil Company, Limited
    Inventors: Ryoji Ohba, Yoshihito Tamanoi