Patents by Inventor Akihisa Ushirokawa

Akihisa Ushirokawa 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).

  • Publication number: 20140156853
    Abstract: The computer is connected with a plurality of computer systems each having one or more resources. The computer stores information relating to a network connecting a first computer system, which is a particular computer system of the plurality of the computer systems, and second computer systems which are those other than the particular computer system. The computer computes a set of the second computer systems connected with the first computer system over the network based on the information relating to the network, and retrieves a resource to be provided for use in the first computer system from among the resources held by the second computer systems included in the computed set.
    Type: Application
    Filed: July 12, 2012
    Publication date: June 5, 2014
    Applicant: NEC CORPORATION
    Inventors: Shinichiro Suda, Akihisa Ushirokawa, Yohei Hayashi
  • Patent number: 8098743
    Abstract: In a pilot signal transmission method for raising the SIR measurement accuracy for transmission power control during high-speed transmission and thus reducing the block error rate and improving the throughput, a first SIR value measured by first pilot signals and second SIR value measured by second pilot signals are first compared, and the presence or absence of second pilot signals then determined in slot units based on the comparison results. When the second pilot signals exist, the second pilot signals are used in addition to the first pilot signals in the SIR measurement for high-speed closed-loop transmission power control. When the second pilot signals do not exist, only the first pilot signals are used in the SIR measurement for high-speed closed-loop transmission power control.
    Type: Grant
    Filed: August 4, 2005
    Date of Patent: January 17, 2012
    Assignee: NEC Corporation
    Inventors: Nahoko Kuroda, Jinsock Lee, Kojiro Hamabe, Akihisa Ushirokawa
  • Publication number: 20110243028
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: June 15, 2011
    Publication date: October 6, 2011
    Applicant: NEC CORPORATION
    Inventors: Akihisa USHIROKAWA, Kojiro HAMABE
  • Publication number: 20110243049
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: June 15, 2011
    Publication date: October 6, 2011
    Applicant: NEC CORPORATION
    Inventors: Akihisa USHIROKAWA, Kojiro HAMABE
  • Publication number: 20110176533
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: March 29, 2011
    Publication date: July 21, 2011
    Applicant: NEC CORPORATION
    Inventors: Akihisa USHIROKAWA, Kojiro HAMABE
  • Publication number: 20110176470
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: March 29, 2011
    Publication date: July 21, 2011
    Applicant: NEC CORPORATION
    Inventors: Akihisa USHIROKAWA, Kojiro HAMABE
  • Patent number: 7944950
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Grant
    Filed: December 8, 2006
    Date of Patent: May 17, 2011
    Assignee: NEC Corporation
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe
  • Patent number: 7940811
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefore, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Grant
    Filed: November 14, 2006
    Date of Patent: May 10, 2011
    Assignee: NEC Corporation
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe
  • Patent number: 7830829
    Abstract: An FDD/CDMA transmission/reception system includes a CDMA transmitter and a CDMA receiver. The CDMA transmitter includes a plurality of transmission antennas, signal transmission units for transmitting transmission signals weighted by different values to the respective transmission antennas, and pilot signal transmission units for transmitting a plurality of different pilot signals to the respective transmission antennas. The CDMA receiver includes a reception unit for obtaining one received signal from the transmission signals from the plurality of transmission antennas of the CDMA transmitter in consideration of reception quality, and a unit for transmitting antenna control signals corresponding to reception power values of the received pilot signals to the CDMA transmitter.
    Type: Grant
    Filed: December 20, 2006
    Date of Patent: November 9, 2010
    Assignee: NEC Corporation
    Inventors: Shousei Yoshida, Akihisa Ushirokawa
  • Patent number: 7417975
    Abstract: To provide a cellular system for enhancing precision of judgement by rendering the number of code words to be judgement candidates at a base station as small as possible and thus improving the efficiency of using the code words. A base station control unit notifies the base station of the maximum number of the base stations on which a mobile station may set up links to allow the base station to limit the code word judgement candidates that may be received. Accordingly, it is possible to increase the distance between the codes among the code words to be the judgement candidates, consequently allowing the base station to reduce judgement errors of the code word.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: August 26, 2008
    Assignee: NEC Corporation
    Inventors: Nahoko Takano, Kojiro Hamabe, Akihisa Ushirokawa
  • Patent number: 7324470
    Abstract: An FDD/CDMA transmission/reception system includes a CDMA transmitter and a CDMA receiver. The CDMA transmitter includes a plurality of transmission antennas, signal transmission units for transmitting transmission signals weighted by different values to the respective transmission antennas, and pilot signal transmission units for transmitting a plurality of different pilot signals to the respective transmission antennas. The CDMA receiver includes a reception unit for obtaining one received signal from the transmission signals from the plurality of transmission antennas of the CDMA transmitter in consideration of reception quality, and a unit for transmitting antenna control signals corresponding to reception power values of the received pilot signals to the CDMA transmitter.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: January 29, 2008
    Assignee: NEC Corporation
    Inventors: Shousei Yoshida, Akihisa Ushirokawa
  • Publication number: 20070297381
    Abstract: A radio communication system for covering a service area with a plurality of cells and dividing and allocating a system band of each cell to a mobile station has a division pattern server and a base station. The division pattern server decides a division pattern indicating a pattern of dividing the system band which is commonly applied to a predetermined range to which the plurality of cells belong. The base station divides the system band into two or more bands, using the division pattern decided by the division pattern server, and allocates the band as a pilot transmission frequency band to the mobile station accommodated in the cell constructed by the base station.
    Type: Application
    Filed: June 12, 2007
    Publication date: December 27, 2007
    Applicant: NEC CORPORATION
    Inventors: Kengo Oketani, Yoshikazu Kakura, Akihisa Ushirokawa
  • Publication number: 20070253450
    Abstract: In a pilot signal transmission method for raising the SIR measurement accuracy for transmission power control during high-speed transmission and thus reducing the block error rate and improving the throughput, a first SIR value measured by first pilot signals and second SIR value measured by second pilot signals are first compared, and the presence or absence of second pilot signals then determined in slot units based on the comparison results. When the second pilot signals exist, the second pilot signals are used in addition to the first pilot signals in the SIR measurement for high-speed closed-loop transmission power control. When the second pilot signals do not exist, only the first pilot signals are used in the SIR measurement for high-speed closed-loop transmission power control.
    Type: Application
    Filed: August 4, 2005
    Publication date: November 1, 2007
    Inventors: Nahoko Kuroda, Jinsock Lee, Kojiro Hamabe, Akihisa Ushirokawa
  • Patent number: 7257408
    Abstract: A radio communication system for quickly selecting an optimum transmission mode in accordance with the quality and situation of a propagation path is provided. The system comprises first and second radio communication apparatuses capable of radio-communicating with each other. The first radio communication apparatus comprises a propagation path environment estimator for outputting the estimation result as propagation path environment information, a propagation path quality estimator for outputting the estimation result as propagation path quality, and a transmitter for transmitting both the informations to the second radio communication apparatus. The second radio communication apparatus comprises a transmission mode selector for selecting one of the transmission modes used for communicating with the first radio communication.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: August 14, 2007
    Assignee: NEC Corporation
    Inventors: Shingo Kikuchi, Shousei Yoshida, Yoshikazu Kakura, Akihisa Ushirokawa, Masayuki Kimata
  • Publication number: 20070104154
    Abstract: An FDD/CDMA transmission/reception system includes a CDMA transmitter and a CDMA receiver. The CDMA transmitter includes a plurality of transmission antennas, signal transmission units for transmitting transmission signals weighted by different values to the respective transmission antennas, and pilot signal transmission units for transmitting a plurality of different pilot signals to the respective transmission antennas. The CDMA receiver includes a reception unit for obtaining one received signal from the transmission signals from the plurality of transmission antennas of the CDMA transmitter in consideration of reception quality, and a unit for transmitting antenna control signals corresponding to reception power values of the received pilot signals to the CDMA transmitter.
    Type: Application
    Filed: December 20, 2006
    Publication date: May 10, 2007
    Applicant: NEC Corporation
    Inventors: Shousei Yoshida, Akihisa Ushirokawa
  • Publication number: 20070081501
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: December 8, 2006
    Publication date: April 12, 2007
    Applicant: NEC CORPORATION
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe
  • Patent number: 7203208
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefore, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Grant
    Filed: January 23, 2003
    Date of Patent: April 10, 2007
    Assignee: NEC Corporation
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe
  • Publication number: 20070058593
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Application
    Filed: November 14, 2006
    Publication date: March 15, 2007
    Applicant: NEC CORPORATION
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe
  • Publication number: 20070010209
    Abstract: According to a communication control method of the present invention, in a communication system provided with pluralities of antennas on a transmission side and reception side, respectively, when a reception side detects a state change from a normal state to an abnormal state or a state change from an abnormal state to a normal state in any reception section among the plurality of reception sections, the reception side calculates a number equal to or less than a number of normal reception sections, as the number of the transmission sections in the transmission side, and transmits transmission section number information, which is information of the calculated number of transmission sections, to the transmission side, and when the transmission side receives the transmission section number information from the reception side, a number of transmission sections that are to be operated is matched with the number indicated by the transmission section number information.
    Type: Application
    Filed: June 29, 2006
    Publication date: January 11, 2007
    Inventors: Hideki Nishizaki, Akihisa Ushirokawa
  • Patent number: 7154915
    Abstract: In the communication system performing transmission with generating the vacant period in the slotted mode during data transmission in order to perform various process, such as different frequency carrier quality measurement or so forth, the control signal for maintaining a communication quality is inserted even in the vacant period. Therefor, a link quality may not be degraded even if the vacant period is long. Namely, when the pilot signal is used as the control signal, even in the vacant period, measurement of the link quality of the forward link with the pilot signal is performed in the mobile station to report the result of measurement to the base station. Therefore, transmission power control of the forward link can be performed according to the report in the base station. Therefore, degradation of the forward link can be eliminated.
    Type: Grant
    Filed: April 6, 1999
    Date of Patent: December 26, 2006
    Assignee: NEC Corporation
    Inventors: Akihisa Ushirokawa, Kojiro Hamabe