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).
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Publication number: 20140156853Abstract: 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: ApplicationFiled: July 12, 2012Publication date: June 5, 2014Applicant: NEC CORPORATIONInventors: Shinichiro Suda, Akihisa Ushirokawa, Yohei Hayashi
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Patent number: 8098743Abstract: 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: GrantFiled: August 4, 2005Date of Patent: January 17, 2012Assignee: NEC CorporationInventors: Nahoko Kuroda, Jinsock Lee, Kojiro Hamabe, Akihisa Ushirokawa
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Publication number: 20110243028Abstract: 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: ApplicationFiled: June 15, 2011Publication date: October 6, 2011Applicant: NEC CORPORATIONInventors: Akihisa USHIROKAWA, Kojiro HAMABE
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Publication number: 20110243049Abstract: 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: ApplicationFiled: June 15, 2011Publication date: October 6, 2011Applicant: NEC CORPORATIONInventors: Akihisa USHIROKAWA, Kojiro HAMABE
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Publication number: 20110176533Abstract: 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: ApplicationFiled: March 29, 2011Publication date: July 21, 2011Applicant: NEC CORPORATIONInventors: Akihisa USHIROKAWA, Kojiro HAMABE
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Publication number: 20110176470Abstract: 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: ApplicationFiled: March 29, 2011Publication date: July 21, 2011Applicant: NEC CORPORATIONInventors: Akihisa USHIROKAWA, Kojiro HAMABE
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Patent number: 7944950Abstract: 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: GrantFiled: December 8, 2006Date of Patent: May 17, 2011Assignee: NEC CorporationInventors: Akihisa Ushirokawa, Kojiro Hamabe
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Patent number: 7940811Abstract: 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: GrantFiled: November 14, 2006Date of Patent: May 10, 2011Assignee: NEC CorporationInventors: Akihisa Ushirokawa, Kojiro Hamabe
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Patent number: 7830829Abstract: 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: GrantFiled: December 20, 2006Date of Patent: November 9, 2010Assignee: NEC CorporationInventors: Shousei Yoshida, Akihisa Ushirokawa
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Patent number: 7417975Abstract: 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: GrantFiled: February 20, 2002Date of Patent: August 26, 2008Assignee: NEC CorporationInventors: Nahoko Takano, Kojiro Hamabe, Akihisa Ushirokawa
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Patent number: 7324470Abstract: 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: GrantFiled: September 21, 2001Date of Patent: January 29, 2008Assignee: NEC CorporationInventors: Shousei Yoshida, Akihisa Ushirokawa
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Publication number: 20070297381Abstract: 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: ApplicationFiled: June 12, 2007Publication date: December 27, 2007Applicant: NEC CORPORATIONInventors: Kengo Oketani, Yoshikazu Kakura, Akihisa Ushirokawa
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Publication number: 20070253450Abstract: 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: ApplicationFiled: August 4, 2005Publication date: November 1, 2007Inventors: Nahoko Kuroda, Jinsock Lee, Kojiro Hamabe, Akihisa Ushirokawa
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Patent number: 7257408Abstract: 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: GrantFiled: June 28, 2004Date of Patent: August 14, 2007Assignee: NEC CorporationInventors: Shingo Kikuchi, Shousei Yoshida, Yoshikazu Kakura, Akihisa Ushirokawa, Masayuki Kimata
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Publication number: 20070104154Abstract: 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: ApplicationFiled: December 20, 2006Publication date: May 10, 2007Applicant: NEC CorporationInventors: Shousei Yoshida, Akihisa Ushirokawa
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Publication number: 20070081501Abstract: 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: ApplicationFiled: December 8, 2006Publication date: April 12, 2007Applicant: NEC CORPORATIONInventors: Akihisa Ushirokawa, Kojiro Hamabe
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Patent number: 7203208Abstract: 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: GrantFiled: January 23, 2003Date of Patent: April 10, 2007Assignee: NEC CorporationInventors: Akihisa Ushirokawa, Kojiro Hamabe
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Publication number: 20070058593Abstract: 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: ApplicationFiled: November 14, 2006Publication date: March 15, 2007Applicant: NEC CORPORATIONInventors: Akihisa Ushirokawa, Kojiro Hamabe
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Publication number: 20070010209Abstract: 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: ApplicationFiled: June 29, 2006Publication date: January 11, 2007Inventors: Hideki Nishizaki, Akihisa Ushirokawa
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Patent number: 7154915Abstract: 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: GrantFiled: April 6, 1999Date of Patent: December 26, 2006Assignee: NEC CorporationInventors: Akihisa Ushirokawa, Kojiro Hamabe