Patents by Inventor Masaaki Shida

Masaaki Shida 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: 9100082
    Abstract: A radio communication system for a communication between a base station and a mobile terminal. The radio communication system repeats a signal transmitted from the base station at repeaters that are multistage-connected by a leaky coaxial cable. Each repeater converts a frequency of an input signal into a different frequency and outputs the frequency-converted signal to the leaky coaxial cable connected to the repeater. The repeaters are provided between the leaky coaxial cables connected in series.
    Type: Grant
    Filed: August 5, 2011
    Date of Patent: August 4, 2015
    Assignee: HITACHI METALS, LTD.
    Inventor: Masaaki Shida
  • Patent number: 8923908
    Abstract: A distributed antenna system includes a first antenna disposed covering a predetermined communication range, the first antenna carrying out a communication at least at a low-frequency band, and a plurality of second antennas disposed covering the predetermined communication range, the plurality of second antennas carrying out a communication at a high-frequency band. The distributed antenna system is operable to carry out a communication between the first antenna and the second antennas, and a mobile terminal located within the predetermined communication range by means of carrier aggregation using the low-frequency band and the high-frequency band. The distributed antenna system further includes a BB module equipped in a base station for carrying out a communication within the predetermined communication range, the first antenna and the second antennas being each connected to the one BB module via an RF module.
    Type: Grant
    Filed: July 14, 2011
    Date of Patent: December 30, 2014
    Assignee: Hitachi Metals, Ltd.
    Inventor: Masaaki Shida
  • Patent number: 8494076
    Abstract: In a MIMO wireless communication system, the transformation process synthesizes the eigenmodes having a large singular value (i.e. a high effective SNR) and the eigenmodes having a small singular value (i.e. a low effective SNR). Thereby, the former eigenmodes are converted into modes having suppressed effective SNR which do not require a large number of levels of modulation, and the latter eigenmodes are converted into modes having increased effective SNR instead. In a MIMO wireless communication system for eigenmode transmission, a large communication capacity is realized without increasing the number of levels of modulation even in a communication environment capable of achieving a high SNR.
    Type: Grant
    Filed: October 12, 2010
    Date of Patent: July 23, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Shigenori Hayase, Masaaki Shida, Keisuke Yamamoto
  • Patent number: 8363634
    Abstract: In a system in which a host and a plurality of terminals simultaneously communicate with each other under the SDMA scheme, transmission parameters to be used for generating frames for SDMA transmission to the respective terminals are adjusted in consideration of the transmission time durations necessary for transmission of other frames to be transmitted simultaneously with the first-mentioned frames, so that differences between the frame transmission time durations are reduced.
    Type: Grant
    Filed: May 1, 2007
    Date of Patent: January 29, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Keisuke Yamamoto, Shigenori Hayase, Masaaki Shida
  • Publication number: 20120308238
    Abstract: A distributed antenna system includes a first antenna disposed covering a predetermined communication range, the first antenna carrying out a communication at least at a low-frequency band, and a plurality of second antennas disposed covering the predetermined communication range, the plurality of second antennas carrying out a communication at a high-frequency band. The distributed antenna system is operable to carry out a communication between the first antenna and the second antennas, and a mobile terminal located within the predetermined communication range by means of carrier aggregation using the low-frequency band and the high-frequency band. The distributed antenna system further includes a BB module equipped in a base station for carrying out a communication within the predetermined communication range, the first antenna and the second antennas being each connected to the one BB module via an RF module.
    Type: Application
    Filed: July 14, 2011
    Publication date: December 6, 2012
    Applicant: HITACHI CABLE, LTD.
    Inventor: Masaaki SHIDA
  • Patent number: 8310995
    Abstract: In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.
    Type: Grant
    Filed: May 2, 2007
    Date of Patent: November 13, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Shinji Murai, Tomoaki Ishifuji, Takashi Yano, Masaaki Shida, Shigenori Hayase
  • Publication number: 20120207065
    Abstract: A radio communication system for a communication between a base station and a mobile terminal. The radio communication system repeats a signal transmitted from the base station at repeaters that are multistage-connected by a leaky coaxial cable. Each repeater converts a frequency of an input signal into a different frequency and outputs the frequency-converted signal to the leaky coaxial cable connected to the repeater. The repeaters are provided between the leaky coaxial cables connected in series.
    Type: Application
    Filed: August 5, 2011
    Publication date: August 16, 2012
    Applicant: Hitachi Cable, LTD.
    Inventor: Masaaki Shida
  • Patent number: 8184724
    Abstract: In a wireless communication system in which a sending side derives transmit weight vectors based on feedback information and carries out precoding, performance degradation is caused when the channel at the time when the transmit weight vectors are derived and the true channel are different from each other. Along with variations in the channel, the power allocation to a plurality of effective streams formed in MIMO is caused to approach asymptotically to uniform power allocation from the value determined based on the channel state information that the sending side has.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: May 22, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Keisuke Yamamoto, Masaaki Shida
  • Patent number: 8155219
    Abstract: A method for suppressing the peak-to-average power ratio (PAPR) while limiting deterioration in signal characteristics in wireless communication devices utilizing wireless communication methods (OFDM method, MIMO method) for multiplexing and sending multiple signals. A weight calculator unit sets a large weight for transmit signals whose channel quality is poor, relative to the weight of each base component based on the acquired channel quality. A peak detector unit detects the peak from the signal string after unitary conversion, and extracts a distortion component to apply for suppressing the peak. A peak suppression signal generation unit calculates the peak signal from the distortion component and weight of each base component, to add to each base component, and adds the peak suppression signal to each base component prior to unitary transformation.
    Type: Grant
    Filed: July 18, 2008
    Date of Patent: April 10, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Shigenori Hayase, Takashi Yano, Masaaki Shida, Keisuke Yamamoto, Yunjian Jia
  • Patent number: 8111667
    Abstract: In a MIMO wireless transceiver, priority control that judges priority of transmit data and a transmission mode table are provided to control an option as to which transmission system SDM or STBC is selected, coding rate and modulation method based on a transmission mode for a transmission destination that is determined by priority of transmission data and status of a communication matrix at the time of data transmission. With such arrangement, a wireless communication system composed of the MIMO wireless transceiver can control coding, MIMO signal processing and modulation methods according to priority of transmit data. More specifically, it is possible to ensure transmission of data having higher priority and improve throughput in total when a plurality of types of data are transmitted.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: February 7, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Shida, Tatemi Ido
  • Publication number: 20110243203
    Abstract: In a wireless communication system in which a sending side derives transmit weight vectors based on feedback information and carries out precoding, performance degradation is caused when the channel at the time when the transmit weight vectors are derived and the true channel are different from each other. Along with variations in the channel, the power allocation to a plurality of effective streams formed in MIMO is caused to approach asymptotically to uniform power allocation from the value determined based on the channel state information that the sending side has.
    Type: Application
    Filed: December 9, 2008
    Publication date: October 6, 2011
    Applicant: Hitachi, Ltd.
    Inventors: Keisuke Yamamoto, Masaaki Shida
  • Publication number: 20110033005
    Abstract: In a MIMO wireless communication system, the transformation process synthesizes the eigenmodes having a large singular value (i.e. a high effective SNR) and the eigenmodes having a small singular value (i.e. a low effective SNR). Thereby, the former eigenmodes are converted into modes having suppressed effective SNR which do not require a large number of levels of modulation, and the latter eigenmodes are converted into modes having increased effective SNR instead. In a MIMO wireless communication system for eigenmode transmission, a large communication capacity is realized without increasing the number of levels of modulation even in a communication environment capable of achieving a high SNR.
    Type: Application
    Filed: October 12, 2010
    Publication date: February 10, 2011
    Inventors: Shigenori Hayase, Masaaki Shida, Keisuke Yamamota
  • Publication number: 20100278279
    Abstract: A MIMO wireless data transmission system including a data arrangement in which data to be sent is divided for each transmission stream of MIMO with adding an error detection code thereto and thereby resending a subframe's worth of data when an error occurred at the time of resending. It therefore becomes to avoid the same frame being sent again at the time of resending.
    Type: Application
    Filed: July 9, 2010
    Publication date: November 4, 2010
    Inventors: Masaaki Shida, Shigenori Hayase, Keisuke Yamamoto
  • Patent number: 7817741
    Abstract: In a MIMO wireless communication system, the transformation process synthesizes the eigenmodes having a large singular value (i.e. a high effective SNR) and the eigenmodes having a small singular value (i.e. a low effective SNR). Thereby, the former eigenmodes are converted into modes having suppressed effective SNR which do not require a large number of levels of modulation, and the latter eigenmodes are converted into modes having increased effective SNR instead. In a MIMO wireless communication system for eigenmode transmission, a large communication capacity is realized without increasing the number of levels of modulation even in a communication environment capable of achieving a high SNR.
    Type: Grant
    Filed: April 17, 2007
    Date of Patent: October 19, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Shigenori Hayase, Masaaki Shida, Keisuke Yamamoto
  • Patent number: 7773686
    Abstract: A MIMO wireless data transmission system including a data arrangement in which data to be sent is divided for each transmission stream of MIMO with adding an error detection code thereto and thereby resending a subframe's worth of data when an error occurred at the time of resending. It therefore becomes to avoid the same frame being sent again at the time of resending.
    Type: Grant
    Filed: April 11, 2007
    Date of Patent: August 10, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Shida, Shigenori Hayase, Keisuke Yamamoto
  • Patent number: 7660288
    Abstract: Disclosed is a wireless communication system capable of performing demodulation at the receiving side without substantially deteriorating BER characteristics, regardless of carrier frequency error existing among plural wireless communication systems in SDMA of uplink. The wireless communication system includes plural antennas; a MIMO processor that decomposes a reception signal the plural antennas received from plural transmitters into transmission signals transmitted from the respective transmitters; a FFT processor that carries out OFDM demodulation; and a demapping unit that obtains data from signals which were previously converted into sub-carrier signals by the FFT processor, in which the MIMO processor is installed ahead of the FFT processor for sake of the processing sequence of a receive signal, and even though a carrier frequency offset exists in the reception signal MIMO processing is performed prior to OFDM demodulation to split the reception signal from plural transmitters.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: February 9, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Shida, Shigenori Hayase, Tomoaki Ishifuji
  • Publication number: 20090147838
    Abstract: In a MIMO wireless transceiver, priority control that judges priority of transmit data and a transmission mode table are provided to control an option as to which transmission system SDM or STBC is selected, coding rate and modulation method based on a transmission mode for a transmission destination that is determined by priority of transmission data and status of a communication matrix at the time of data transmission. With such arrangement, a wireless communication system composed of the MIMO wireless transceiver can control coding, MIMO signal processing and modulation methods according to priority of transmit data. More specifically, it is possible to ensure transmission of data having higher priority and improve throughput in total when a plurality of types of data are transmitted.
    Type: Application
    Filed: February 9, 2009
    Publication date: June 11, 2009
    Inventors: Masaaki Shida, Tatemi Ido
  • Publication number: 20090060070
    Abstract: A method for suppressing the peak-to-average power ratio (PAPR) while limiting deterioration in signal characteristics in wireless communication devices utilizing wireless communication methods (OFDM method, MIMO method) for multiplexing and sending multiple signals. A weight calculator unit sets a large weight for transmit signals whose channel quality is poor, relative to the weight of each base component based on the acquired channel quality. A peak detector unit detects the peak from the signal string after unitary conversion, and extracts a distortion component to apply for suppressing the peak. A peak suppression signal generation unit calculates the peak signal from the distortion component and weight of each base component, to add to each base component, and adds the peak suppression signal to each base component prior to unitary transformation.
    Type: Application
    Filed: July 18, 2008
    Publication date: March 5, 2009
    Inventors: Shigenori Hayase, Takashi Yano, Masaaki Shida, Keisuke Yamamoto, Yunjian Jia
  • Patent number: 7493092
    Abstract: In a MIMO wireless transceiver, priority control that judges priority of transmit data and a transmission mode table are provided to control an option as to which transmission system SDM or STBC is selected, coding rate and modulation method based on a transmission mode for a transmission destination that is determined by priority of transmission data and status of a communication matrix at the time of data transmission. With such arrangement, a wireless communication system composed of the MIMO wireless transceiver can control coding, MIMO signal processing and modulation methods according to priority of transmit data. More specifically, it is possible to ensure transmission of data having higher priority and improve throughput in total when a plurality of types of data are transmitted.
    Type: Grant
    Filed: August 26, 2005
    Date of Patent: February 17, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Shida, Tatemi Ido
  • Publication number: 20080267133
    Abstract: When a plurality of user stations (STAs) simultaneously communicate with an access point (AP) through an SDMA (Space Division Multiple Access) channel in a MIMO wireless communication system, these STAs control their respective transmission signals such that each signal is received by only a different one of the plurality of antennas at the AP. (It should be noted that the number of these STAs is equal to or smaller than the number of antennas at the AP.) This eliminates the need for the AP to perform MIMO processing, thereby allowing the AP to properly receive and demodulate the signals even if they differ in carrier frequency and transmission timing, which would otherwise result in communication degradation or failure.
    Type: Application
    Filed: February 15, 2008
    Publication date: October 30, 2008
    Inventors: Masaaki Shida, Takashi Yano, Shigenori Hayase, Keisuke Yamamoto