Patents by Inventor Hideki Nakahara

Hideki Nakahara 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: 20210226590
    Abstract: A method, apparatus and computer program is described comprising: determining an absolute gain of a power amplifier over time, wherein the absolute gain is formed from the division of a feedback baseband signal derived (e.g. by demodulating an RF signal) from an output of the power amplifier, by a forward baseband signal that is used to form an input of the power amplifier; determining a relative gain transient response (GTR) of the power amplifier, by normalising the absolute gain to generate a relative gain of the power amplifier over time; and determining a transient response compensation value having inverse characteristics to the relative gain transient response.
    Type: Application
    Filed: June 19, 2018
    Publication date: July 22, 2021
    Inventor: Hideki NAKAHARA
  • Patent number: 8675759
    Abstract: A wireless transmission system performs multi-station simultaneous transmission of data. The wireless transmission system includes wireless stations for transmitting and receiving data. Transmitter-side wireless stations, a multipath channel, and receiver-side wireless stations constitute a system for path diversity. At least one wireless station among the wireless stations determines, depending on a response packet with respective to a multi-station simultaneous transmission request packet transmitted by itself or other stations, delay amounts from a reference timing during multi-station simultaneous transmission in the wireless transmission system, and symbol waveforms that are a basis for a modulated waveform. A difference between each delay amount is set to be larger than or equal to a predetermined delay resolution for each symbol waveform, and a difference between maximum and minimum values of the delay amounts is set to be smaller than or equal to a predetermined maximum delay.
    Type: Grant
    Filed: March 20, 2007
    Date of Patent: March 18, 2014
    Assignee: Panasonic Corporation
    Inventors: Hitoshi Takai, Hidetoshi Yamasaki, Hideki Nakahara, Kenji Miyanaga
  • Patent number: 8229015
    Abstract: A wireless transmission system capable of exerting a maximum path diversity effect by using combinations formed by symbol waveforms. A transmission timing controlling section (23) determines a transmission start timing. A modulating section (21) modulates a signal by using one of a plurality of symbol waveform candidates and by utilizing a modulation scheme in which a phase transition of a symbol waveform represents a waveform being changed, and then transmits the modulated signal at a transmission start timing. A predetermined delay amount is set such that (i) the number of reception timings, each indicating a timing at which a receiving station (12) receives a signal, is a plural number and is less than or equal to a maximum number of effective branches for each symbol waveform, and (ii) each time difference between the reception timings is greater than or equal to a delay resolution and less than or equal to a maximum delay.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: July 24, 2012
    Assignee: Panasonic Corporation
    Inventors: Hitoshi Takai, Kenji Miyanaga, Hideki Nakahara, Hidetoshi Yamasaki
  • Patent number: 8170130
    Abstract: A transmission device includes a differential encoding section for differentially encoding transmission data, a first waveform generation section, a second waveform generation section, and two transmission antennas. A reception device includes a reception antenna, a delay detection section, and a data determination section for low-pass filtering a delay detection signal. The reception device receives modulated signals modulated by using two waveforms having low correlations with each other. Thus, regardless of the presence or absence of delay dispersion in a propagation path and even in a high-speed fading in which the propagation path varies at high speed, a transmission diversity effect can be achieved, thereby making it possible to improve transmission characteristics.
    Type: Grant
    Filed: March 24, 2006
    Date of Patent: May 1, 2012
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Hitoshi Takai, Koichiro Tanaka
  • Patent number: 8170162
    Abstract: An inter-carrier interface removal device can improve estimation accuracy of inter-carrier interference caused by Doppler shift in a received multi-carrier signal moving at a high speed, and a reception characteristic of the multi-carrier signal after removing the inter-carrier interference.
    Type: Grant
    Filed: April 14, 2011
    Date of Patent: May 1, 2012
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Yoshinobu Matsumura, Mikihiro Ouchi, Tomohiko Taniguchi
  • Patent number: 8050620
    Abstract: A wireless station is used as one of a plurality of relay stations forming transmission paths, respectively, different from each other, in a wireless transmission system for transmitting a packet from a transmitting station to a receiving station through the plurality of relay stations. The wireless station includes a reception section for receiving a packet transmitted from the transmitting station, and receiving a packet which is transmitted, based on the packet transmitted from the transmitting station, from another relay station, and is transmitted before the one of the plurality of relay stations performs transmission, by using a transmission parameter for obtaining a path diversity effect in the wireless transmission system.
    Type: Grant
    Filed: January 31, 2007
    Date of Patent: November 1, 2011
    Assignee: Panasonic Corporation
    Inventors: Kenji Miyanaga, Hitoshi Takai, Hideki Nakahara, Hidetoshi Yamasaki
  • Publication number: 20110211630
    Abstract: An inter-carrier interface removal device can improve estimation accuracy of inter-carrier interference caused by Doppler shift in a received multi-carrier signal moving at a high speed, and a reception characteristic of the multi-carrier signal after removing the inter-carrier interference.
    Type: Application
    Filed: April 14, 2011
    Publication date: September 1, 2011
    Inventors: HIDEKI NAKAHARA, YOSHINOBU MATSUMURA, MIKIHIRO OUCHI, TOMOHIKO TANIGUCHI
  • Patent number: 7991089
    Abstract: An inter-carrier interface removal device can improve estimation accuracy of inter-carrier interference caused by Doppler shift in a received multi-carrier signal moving at a high speed, and a reception characteristic of the multi-carrier signal after removing the inter-carrier interference.
    Type: Grant
    Filed: October 20, 2006
    Date of Patent: August 2, 2011
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Yoshinobu Matsumura, Mikihiro Ouchi, Tomohiko Taniguchi
  • Patent number: 7899139
    Abstract: A detected signal 111 contains a preamble portion which includes symbol alternations, followed by a unique word portion, and a data portion. Each time a symbol alternation is detected, a correction value calculation section 102 averages the phase shift in the detected signal 111 for a predetermined length, thereby calculating a correction value 115. The correction value determination section 103 stores a plurality of correction values 115 in a chronological order. When the unique word portion is detected, the correction value determination section 103 retains, as an effective correction value 118, a correction value which is arrived at by going back a predetermined number of correction values among the stored correction values. A phase rotation section 104 corrects the phase of the detected signal 111 by using an effective correction value 118 calculated by the correction value determination section 103.
    Type: Grant
    Filed: January 3, 2008
    Date of Patent: March 1, 2011
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Koichiro Tanaka, Kenichi Mori, Yoshio Urabe, Hitoshi Takai
  • Patent number: 7843972
    Abstract: In an OFDM transmission method, in order to compensate any frequency response variation time wise resulted from any distortion in a transmission path, out-of-synchronization with passage of time, frequency drift, and phase shift, and to improve a demodulation characteristic, a PS detector in a receiver receiving an OFDM signal detects a pilot symbol. A PS1 TPFR calculator calculates a frequency response of the transmission path for a first pilot symbol, while a PS2 TPFR calculator calculates a frequency response of the transmission path for a second pilot symbol. Thereafter, a compensation vector calculator calculates compensation vectors from the frequency responses of the transmission path for both the first and second pilot symbols by linear approximation. A frequency response compensator compensates the frequency response variation of subcarriers in a data symbol based on the calculated compensation vectors.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: November 30, 2010
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Koichiro Tanaka, Naganori Shirakata, Tomohiro Kimura, Yasuo Harada
  • Publication number: 20100239039
    Abstract: A wireless transmission system capable of performing multi-station simultaneous transmission of data by wireless is provided. The wireless transmission system includes a plurality of wireless stations for transmitting and receiving data. Transmitter-side wireless stations, a multipath channel, and receiver-side wireless stations constitute a system for path diversity. At least one wireless station among the wireless stations determines, depending on a response packet with respective to a multi-station simultaneous transmission request packet transmitted by itself or other stations, a plurality of delay amounts from a reference timing during multi-station simultaneous transmission in the wireless transmission system, and a plurality of symbol waveforms that are a basis for a modulated waveform.
    Type: Application
    Filed: March 20, 2007
    Publication date: September 23, 2010
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Hitoshi Takai, Hidetoshi Yamasaki, Hideki Nakahara, Kenji Miyanaga
  • Patent number: 7756218
    Abstract: A wireless transmission system exerts a maximum path diversity effect even if the maximum number of effective branches is limited to a small number. A transmission timing control section determines a transmission start timing to be a timing obtained by delaying a reference timing by a predetermined delay amount. A modulation section modulates a signal by a modulation scheme such that an anti-multipath property is exerted when the signal is demodulated on a receiver side, and transmits the modulated signal at the transmission start timing. In a receiving station, a demodulation section demodulates the receive signal to obtain receive data.
    Type: Grant
    Filed: September 16, 2005
    Date of Patent: July 13, 2010
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Hitoshi Takai, Hidetoshi Yamasaki, Kenji Miyanaga, Koichiro Tanaka
  • Patent number: 7738540
    Abstract: A wireless transmission system capable of performing a multi-station simultaneous transmission of data, that is, simultaneously transmitting data by wireless to a plurality of stations. The wireless transmission system includes a plurality of wireless stations for transmitting/receiving data and it constitutes a system for path diversity by use of a wireless station at the transmitting end, a multipath transmission path, and a wireless station at the receiving end. At least one of the plurality of wireless stations decides, in accordance with a response packet responsive to a multi-station simultaneous transmission request packet transmitted by the wireless station or other stations, a plurality of delay amounts relative to a reference timing during the multi-station simultaneous transmission in the wireless transmission system.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: June 15, 2010
    Assignee: Panasonic Corporation
    Inventors: Hidetoshi Yamasaki, Hitoshi Takai, Hideki Nakahara, Kenji Miyanaga
  • Patent number: 7724856
    Abstract: A clock recovery circuit capable of fast and accurate clock phase locking even in the presence of frequency shift and noise. The input signal includes, in order, a preamble with an alternating bit sequence pattern, a unique word and data. A detection unit detects zero crossings and measures the time interval therebetween. A 1-interval judgment unit judges whether an interval signal is within a predetermined range, and a 2-interval judgment unit sums two adjacent interval signals and judges whether the 2-interval signal is within a predetermined range. A control unit controls a zero-crossing signal based on the judgment result and outputs a valid zero-crossing signal if judged in the affirmative. A switching unit switches between outputting the zero-crossing signal and the valid zero-crossing signal as valid phase error information based on a frame reception signal input from a frame detection unit. A clock generation unit uses the valid phase error information in generating a symbol clock.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: May 25, 2010
    Assignee: Panasonic Corporation
    Inventors: Hideki Nakahara, Tomohiro Kimura, Hitoshi Takai, Kenichi Mori
  • Patent number: 7664093
    Abstract: A wireless station capable of increasing the probability that a path diversity effect can be obtained in a case where a plurality of wireless stations transmit packets using a modulation/demodulation scheme with an anti-multipath property. A delay amount determining section (48) randomly selects a delay amount from among a plurality of candidate values. A transmission timing control section (47) determines a transmission start timing, at which to start the packet transmission, to be a timing obtained by delaying a reference timing by the delay amount selected by the delay amount determining section. At the transmission start timing, a modulation section (49) transmits the packet via an RF section (42) and an antenna (41). The difference between the candidate values is greater than or equal to a predetermined delay resolution, and the difference between a maximum candidate value and a minimum candidate value is less than or equal to a predetermined maximum delay.
    Type: Grant
    Filed: September 16, 2005
    Date of Patent: February 16, 2010
    Assignee: Panasonic Corporation
    Inventors: Kenji Miyanaga, Hideki Nakahara, Hidetoshi Yamasaki, Hitoshi Takai
  • Publication number: 20090225913
    Abstract: An inter-carrier interface removal device can improve estimation accuracy of inter-carrier interference caused by Doppler shift in a received multi-carrier signal moving at a high speed, and a reception characteristic of the multi-carrier signal after removing the inter-carrier interference.
    Type: Application
    Filed: October 20, 2006
    Publication date: September 10, 2009
    Inventors: Hideki Nakahara, Yoshinobu Matsumura, Mikihiro Ouchi, Tomohiko Taniguchi
  • Publication number: 20090097584
    Abstract: The present invention provides a wireless transmission system capable of exerting a maximum path diversity effect by using combinations formed by a plurality of symbol waveforms even when a maximum number of effective branches is limited to a small number. A transmission timing controlling section (23) determines a timing delayed from a reference timing by a predetermined delay amount as a transmission start timing. A modulating section (21) modulates a signal, by using one symbol waveform among a plurality of symbol waveform candidates, utilizing a modulation scheme in which a phase transition of a symbol waveform, which exerts an anti-multipath property by demodulating the signal on the receiving side, represents a waveform being changed, and then transmits the modulated signal at a transmission start timing.
    Type: Application
    Filed: March 16, 2007
    Publication date: April 16, 2009
    Inventors: Hitoshi Takai, Kenji Miyanaga, Hideki Nakahara, Hidetoshi Yamasaki
  • Publication number: 20090036052
    Abstract: A wireless station according to the present invention is a wireless station used as one of a plurality of relay stations forming transmission paths, respectively, different from each other, in a wireless transmission system for transmitting a packet from a transmitting station to a receiving station through the plurality of relay stations, and the wireless station comprises: a reception section for receiving a packet transmitted from the transmitting station, and receiving a packet which is transmitted, based on the packet transmitted from the transmitting station, from a relay station other than the one of the plurality of relay stations, and is transmitted before the one of the plurality of relay stations performs transmission, by using a transmission parameter for obtaining a path diversity effect in the wireless transmission system; a transmission parameter estimation section for estimating the transmission parameter used by the relay station other than the one of the plurality of relay stations, based on
    Type: Application
    Filed: January 31, 2007
    Publication date: February 5, 2009
    Inventors: Kenji Miyanaga, Hitoshi Takai, Hideki Nakahara, Hidetoshi Yamasaki
  • Publication number: 20080212706
    Abstract: A transmission device (100) includes a differential encoding section (101) for differentially encoding transmission data, a first waveform generation section (102), a second waveform generation section (103), and two transmission antennas (109 and 110). A reception device (140) includes a reception antenna (141), a delay detection section (144), and a data determination section (145) for low-pass filtering a delay detection signal. The reception device (140) receives modulated signals modulated by using two wave forms having low correlations with each other. Thus, regardless of the presence or absence of delay dispersion in a propagation path and even in a high-speed fading in which the propagation path varies at high speed, a transmission diversity effect can be achieved, thereby making it possible to improve transmission characteristics.
    Type: Application
    Filed: March 24, 2006
    Publication date: September 4, 2008
    Inventors: Hideki Nakahara, Hitoshi Takai, Koichiro Tanaka
  • Publication number: 20080198835
    Abstract: The present invention provides a wireless station capable of increasing the probability that a path diversity effect can be obtained in a case where a plurality of wireless stations transmit packets using a modulation/demodulation scheme with an anti-multipath property. A delay amount determining section (48) randomly selects a delay amount from among a plurality of candidate values. A transmission timing control section (47) determines a transmission start timing, at which to start the packet transmission, to be a timing obtained by delaying a reference timing by the delay amount selected by the delay amount determining section. At the transmission start timing, a modulation section (49) transmits the packet via an RF section (42) and an antenna (41). The difference between the candidate values is greater than or equal to a predetermined delay resolution, and the difference between a maximum candidate value and a minimum candidate value is less than or equal to a predetermined maximum delay.
    Type: Application
    Filed: September 16, 2005
    Publication date: August 21, 2008
    Inventors: Kenji Miyanaga, Hideki Nakahara, Hidetoshi Yamasaki, Hitoshi Takai