Patents by Inventor Takanori Iwamatsu
Takanori Iwamatsu 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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Patent number: 10277261Abstract: A distortion compensation apparatus includes: a filtering unit that is provided with a plurality of storing units each of which is capable of storing a signal therein and that filters an input signal by sequentially moving the input signal starting from a storing unit provided on a first stage up to another storing unit provided on a final stage; a calculating unit that calculates a power level of a signal output from a storing unit that is provided on an earlier stage than the storing unit provided on the final stage; an output unit that, on the basis of the power level calculated, outputs a distortion compensation coefficient used for cancelling out non-linear distortion occurring in an amplifier; and a distortion compensation unit that performs a distortion compensation process on a signal output from the storing unit provided on the final stage, by using the distortion compensation coefficient.Type: GrantFiled: May 29, 2018Date of Patent: April 30, 2019Assignee: FUJITSU LIMITEDInventors: Tomohiro Nakamura, Takanori Iwamatsu
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Publication number: 20180367174Abstract: A distortion compensation apparatus includes: a filtering unit that is provided with a plurality of storing units each of which is capable of storing a signal therein and that filters an input signal by sequentially moving the input signal starting from a storing unit provided on a first stage up to another storing unit provided on a final stage; a calculating unit that calculates a power level of a signal output from a storing unit that is provided on an earlier stage than the storing unit provided on the final stage; an output unit that, on the basis of the power level calculated, outputs a distortion compensation coefficient used for cancelling out non-linear distortion occurring in an amplifier; and a distortion compensation unit that performs a distortion compensation process on a signal output from the storing unit provided on the final stage, by using the distortion compensation coefficient.Type: ApplicationFiled: May 29, 2018Publication date: December 20, 2018Applicant: FUJITSU LIMITEDInventors: Tomohiro Nakamura, TAKANORI IWAMATSU
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Patent number: 9647858Abstract: Embodiments of the present invention provide an optimizing apparatus and method for a pulse shaping filter and a transmitter. The apparatus is configured to determine an initial peak-to-average power ratio threshold of the pulse shaping filter, and determine an initial filter coefficient of the pulse shaping filter according to the initial peak-to-average power ratio threshold; determine a constraint condition for optimizing the pulse shaping filter according to the initial peak-to-average power ratio threshold and the initial filter coefficient of the pulse shaping filter; wherein the constraint condition comprises a threshold constraint in a filter coefficient sign domain; and adjust the initial peak-to-average power ratio threshold and the initial filter coefficient of the pulse shaping filter in a case where the constraint condition is satisfied, until a predefined condition is satisfied, so as to obtain an optimized filter coefficient of the pulse shaping filter.Type: GrantFiled: March 31, 2015Date of Patent: May 9, 2017Assignee: FUJITSU LIMITEDInventors: Hui Li, Takanori Iwamatsu, Jianmin Zhou
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Patent number: 9584167Abstract: A wireless communication system including: a first communication device including: a processor configured to: compensate a distortion to a input signal based on a determined distortion compensation coefficient set, a amplifier configured to amplify the input signal to which the distortion is compensated, and a first antenna configured to: transmit the amplified signal to a second communication device, and receive a first feedback signal from the second communication device, the first feedback signal relating to an error that is detected in a received signal by the second communication device, the received signal corresponding to the transmitted signal, wherein a plurality of distortion compensation coefficient included in the determined distortion compensation coefficient set are adjusted based on the first feedback signal relating to the error that is detected in the received signal by the second communication device.Type: GrantFiled: June 19, 2015Date of Patent: February 28, 2017Assignee: FUJITSU LIMITEDInventors: Kazuyoshi Kakinuma, Takanori Iwamatsu
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Patent number: 9504187Abstract: An electronic device housing, includes: a housing case including a housing area which houses a heat generating component; a duct, including ends which are in communication with the housing area at different positions respectively and a body portion disposed outside the housing area, in which first air inside housing case which is heated by the heat generating component flows; and a flow device, disposed in the housing case, configured to circulate the first air and make second air which radiates heat in the duct flow towards a side of the housing area side.Type: GrantFiled: March 4, 2015Date of Patent: November 22, 2016Assignee: Fujitsu LimitedInventors: Yuichi Hagiwara, Takao Tomiyama, Manabu Miyamoto, Hiroshi Yano, Kenichi Oide, Yoshihiro Ito, Takanori Iwamatsu
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Patent number: 9413302Abstract: A digital predistortion apparatus comprising: a nonlinear device; a memory effect compensator; a constant value characteristic acquirer; a cost function generator; and a coefficient updater is described.Type: GrantFiled: July 31, 2014Date of Patent: August 9, 2016Assignee: FUJITSU LIMITEDInventors: Zhan Shi, Hui Li, Jianmin Zhou, Takanori Iwamatsu
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Publication number: 20160028421Abstract: A wireless communication system including: a first communication device including: a processor configured to: compensate a distortion to a input signal based on a determined distortion compensation coefficient set, a amplifier configured to amplify the input signal to which the distortion is compensated, and a first antenna configured to: transmit the amplified signal to a second communication device, and receive a first feedback signal from the second communication device, the first feedback signal relating to an error that is detected in a received signal by the second communication device, the received signal corresponding to the transmitted signal, wherein a plurality of distortion compensation coefficient included in the determined distortion compensation coefficient set are adjusted based on the first feedback signal relating to the error that is detected in the received signal by the second communication device.Type: ApplicationFiled: June 19, 2015Publication date: January 28, 2016Inventors: Kazuyoshi KAKINUMA, Takanori IWAMATSU
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Patent number: 9225363Abstract: The present disclosure provides a digital pre-distortion transmitter and a method for controlling the same, which increase the efficiency of the power amplifier and improve the linearity of the transmitter. The digital pre-distortion transmitter includes: a pre-distortion unit configured to update a pre-distortion coefficient required by pre-distortion processing, and perform the pre-distortion processing on a baseband signal; a signal process and transmit unit configured to perform signal processing on the pre-distortion-processed baseband signal and transmission thereof; and a feedback signal process unit configured to process a feedback signal of the signal transmitted by the signal process and transmit unit, so as to supply a dynamic drain voltage to a power amplifier in the signal process and transmit unit by using the processed feedback signal; and, the pre-distortion unit updates the pre-distortion coefficient by using the feedback signal processed by the feedback signal process unit.Type: GrantFiled: August 29, 2014Date of Patent: December 29, 2015Assignee: FUJITSU LIMITEDInventors: Donglin Wu, Jie Wu, Pei Chen, Jianmin Zhou, Takanori Iwamatsu
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Patent number: 9209913Abstract: Embodiments of the present invention provide a temperature compensation method and apparatus for a received signal strength indicator. The apparatus comprises a temperature sensor configured to measure a current temperature; and a digital compensation module configured to select a temperature compensation coefficient from prestored temperature compensation coefficients corresponding to a normal temperature, a low temperature and a high temperature according to the current temperature, and perform temperature compensation on output signals of the RSSI according to the selected temperature compensation coefficient. With the method and apparatus of the embodiments of the present invention, the accurate power values of the input signals of the RSSI under any temperatures can be obtained by measuring the characteristics of the RSSI under the predefined three temperatures, and using an interpolation method to compensate for the temperature characteristics of the RSSI.Type: GrantFiled: September 27, 2013Date of Patent: December 8, 2015Assignee: FUJITSU LIMITEDInventors: Hui Li, Takanori Iwamatsu, Jianmin Zhou
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Patent number: 9190972Abstract: An automatic gain control device includes: a variable gain adjusting unit, for adjusting an input signal by a variable gain and outputting an adjustment result; an analog-digital converting unit, for performing analog-digital conversion on the adjustment result to obtain an analog-digital conversion result; and a gain determining unit, for determining a distribution status over a predetermined period of time of a maximum or a minimum of the analog-digital conversion result, comparing the distribution status with a first distribution condition, and if the distribution status meets the first distribution condition, then keeping the variable gain unchanged, otherwise changing the variable gain and determining newly a distribution status until the newly determined distribution status meets a second distribution condition which is at least as strict as the first distribution condition.Type: GrantFiled: January 31, 2013Date of Patent: November 17, 2015Assignee: FUJITSU LIMITEDInventors: Hui Li, Takanori Iwamatsu, Jianmin Zhou
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Publication number: 20150280944Abstract: Embodiments of the present invention provide an optimizing apparatus and method for a pulse shaping filter and a transmitter.Type: ApplicationFiled: March 31, 2015Publication date: October 1, 2015Inventors: Hui LI, Takanori Iwamatsu, Jianmin Zhou
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Publication number: 20150271950Abstract: An electronic device housing, includes: a housing case including a housing area which houses a heat generating component; a duct, including ends which are in communication with the housing area at different positions respectively and a body portion disposed outside the housing area, in which first air inside housing case which is heated by the heat generating component flows; and a flow device, disposed in the housing case, configured to circulate the first air and make second air which radiates heat in the duct flow towards a side of the housing area side.Type: ApplicationFiled: March 4, 2015Publication date: September 24, 2015Inventors: Yuichi HAGIWARA, Takao TOMIYAMA, Manabu MIYAMOTO, Hiroshi YANO, Kenichi OIDE, Yoshihiro ITO, Takanori IWAMATSU
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Patent number: 9036736Abstract: A method and apparatus for controlling update of digital pre-distortion (DPD) coefficient is provided. The apparatus is applicable to a digital power control system, wherein the apparatus comprises: an update controlling unit configured to determine a group of fully-trained DPD coefficients among a plurality of DPD coefficients; and a DPD coefficient generating unit configured to update adaptively the group of fully-trained DPD coefficients according to the result of judgment of the update controlling unit. The DPD coefficients are allowed to be updated after being judged as being able to be fully trained according to power distribution information of DPD input signals, or according to address distribution information of an LUT, or according to average power of output of an HPA; otherwise, they may not be updated, thereby efficiently preventing DPD abnormality resulted from unfull training of coefficients in being updated.Type: GrantFiled: August 20, 2013Date of Patent: May 19, 2015Assignee: FUJITSU LIMITEDInventors: Pei Chen, Jianmin Zhou, Takanori Iwamatsu
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Publication number: 20150071382Abstract: The embodiments of the present disclosure provide a digital pre-distortion transmitter and a method for controlling the same, which increase the efficiency of the power amplifier and improve the linearity of the transmitter.Type: ApplicationFiled: August 29, 2014Publication date: March 12, 2015Inventors: Donglin WU, Jie WU, Pei CHEN, Jianmin ZHOU, Takanori IWAMATSU
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Publication number: 20150061773Abstract: A digital predistortion apparatus comprising: a nonlinear device; a memory effect compensator; a constant value characteristic acquirer; a cost function generator; and a coefficient updater is described.Type: ApplicationFiled: July 31, 2014Publication date: March 5, 2015Inventors: Zhan SHI, Hui LI, Jianmin ZHOU, Takanori IWAMATSU
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Patent number: 8971460Abstract: A wireless receiving apparatus includes a spurious component extraction unit, and a spurious cancellation unit. The spurious component extraction unit is configured to cancel a desired wave with a multi-antenna configuration, and extract spurious components. The spurious cancellation unit is configured to cancel spurious in received signals by using the spurious components extracted. A first correlation unit in the spurious component extraction unit finds a correlation between an output of the spurious extraction unit and an output of the spurious cancellation unit.Type: GrantFiled: December 19, 2013Date of Patent: March 3, 2015Assignee: Fujitsu LimitedInventors: Hideki Furudate, Takanori Iwamatsu
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Patent number: 8963633Abstract: An automatic gain control device includes: a variable gain adjusting unit, for adjusting an input signal by a variable gain and outputting an adjustment result; an analog-digital converting unit, for performing analog-digital conversion on the adjustment result to obtain an analog-digital conversion result; and a gain determining unit, for determining a distribution status over a predetermined period of time of a maximum or a minimum of the analog-digital conversion result, comparing the distribution status with a first distribution condition, and if the distribution status meets the first distribution condition, then keeping the variable gain unchanged, otherwise changing the variable gain and determining newly a distribution status until the newly determined distribution status meets a second distribution condition which is at least as strict as the first distribution condition.Type: GrantFiled: January 31, 2013Date of Patent: February 24, 2015Assignee: Fujitsu LimitedInventors: Hui Li, Takanori Iwamatsu, Jianmin Zhou
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Patent number: 8744460Abstract: A radio communication system including a first terminal apparatus group for performing a reception by using a first radio resource and a transmission by using a second radio resource; and a second terminal apparatus group for performing the reception by using the second radio resource and the transmission by using the first radio resource, for performing a direct radio communication. The system includes a first terminal which belongs to the first terminal apparatus group and transmits allocation request of transmission band in the second radio resource by using the second radio resource; and a second terminal which belongs to the second terminal apparatus group, receives the allocation request transmitted from the first terminal, and transmits information indicating allocation of the transmission band for the first terminal, wherein the first terminal transmits data by using the allocated transmission band in the second radio resource.Type: GrantFiled: November 5, 2010Date of Patent: June 3, 2014Assignee: Fujitsu LimitedInventors: Hideki Furudate, Takanori Iwamatsu
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Publication number: 20140105335Abstract: A wireless receiving apparatus includes a spurious component extraction unit, and a spurious cancellation unit. The spurious component extraction unit is configured to cancel a desired wave with a multi-antenna configuration, and extract spurious components. The spurious cancellation unit is configured to cancel spurious in received signals by using the spurious components extracted. A first correlation unit in the spurious component extraction unit finds a correlation between an output of the spurious extraction unit and an output of the spurious cancellation unit.Type: ApplicationFiled: December 19, 2013Publication date: April 17, 2014Applicant: FUJITSU LIMITEDInventors: Hideki FURUDATE, TAKANORI IWAMATSU
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Publication number: 20140094133Abstract: Embodiments of the present invention provide a temperature compensation method and apparatus for a received signal strength indicator. The apparatus comprises a temperature sensor configured to measure a current temperature; and a digital compensation module configured to select a temperature compensation coefficient from prestored temperature compensation coefficients corresponding to a normal temperature, a low temperature and a high temperature according to the current temperature, and perform temperature compensation on output signals of the RSSI according to the selected temperature compensation coefficient. With the method and apparatus of the embodiments of the present invention, the accurate power values of the input signals of the RSSI under any temperatures can be obtained by measuring the characteristics of the RSSI under the predefined three temperatures, and using an interpolation method to compensate for the temperature characteristics of the RSSI.Type: ApplicationFiled: September 27, 2013Publication date: April 3, 2014Applicant: FUJITSU LIMITEDInventors: Hui LI, Takanori IWAMATSU, Jianmin ZHOU