Patents by Inventor Kazunori Akabane
Kazunori Akabane 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: 11923911Abstract: An underwater acoustic communication system includes a transmission device including N transmitters, and a reception device. The reception device includes M (M is an integer of two or more) receivers configured to receive M reception signal sequences corresponding to N transmission signal sequences transmitted from the N transmitters through sound waves, a beam former configured to suppress multipath waves other than direct waves of the M received reception signal sequences and to generate L (L is an integer of two or more) signal sequences from the M reception signal sequences, and a signal estimation unit configured to estimate the N transmission signal sequences based on the L generated signal sequences.Type: GrantFiled: November 14, 2019Date of Patent: March 5, 2024Assignee: Nippon Telegraph and Telephone CorporationInventors: Yosuke Fujino, Hiroyuki Fukumoto, Marina Nakano, Kazunori Akabane
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Patent number: 11888538Abstract: A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.Type: GrantFiled: November 12, 2019Date of Patent: January 30, 2024Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yosuke Fujino, Hiroyuki Fukumoto, Kazunori Akabane
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Patent number: 11848727Abstract: A plurality of transmit antennas of a radio transmission device and a plurality of receive antennas of a radio reception device are located under the sea that is a line-of-sight environment, wherein the radio transmission device selects a frequency channel to be used based on an index value per frequency channel indicating orthogonality between the transmit and receive antennas defined based on a distance between the transmit and receive antennas and an angle indicating a direction of arrival of a radio signal, an interval between the plurality of transmit antennas, an interval between the plurality of receive antennas, and a modulation scheme, the distance between the transmit and receive antennas and the angle indicating the direction of arrival of the radio signal estimated by the radio reception device, and a desired bit error rate to be predetermined, selects the modulation scheme for providing a maximum transmission capacity per the selected frequency channel, separates transmission data into a pluralitType: GrantFiled: August 13, 2019Date of Patent: December 19, 2023Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Marina Nakano, Yosuke Fujino, Hiroyuki Fukumoto, Kazunori Akabane
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Patent number: 11750299Abstract: A communication device includes a channel estimation unit configured to estimate an impulse response based on signals of sound waves received by each of a plurality of hydrophones, a long delay removal unit configured to remove a long-delay impulse response from the impulse response to generate a post-removal impulse response, a weighting factor calculation unit configured to calculate a weighting factor based on the post-removal impulse response, and a synthesizing unit configured to synthesize the signals received by each of the plurality of hydrophones based on the weighting factor.Type: GrantFiled: July 1, 2019Date of Patent: September 5, 2023Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Hiroyuki Fukumoto, Yosuke Fujino, Marina Nakano, Kazunori Akabane
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Patent number: 11553421Abstract: Provided is a wireless communication system in which a first wireless device and a second wireless device intermittently perform wireless communication, in which the first wireless device repeatedly transmits an activation signal for activating the second wireless device at a first cycle until receiving a response signal from the second wireless device, the second wireless device repeatedly executes detection processing of the activation signal at a second cycle that is longer than the first cycle, receives, when a part of the activation signal is detected in the detection processing, the activation signal, transmits, when the activation signal is addressed to the second wireless device itself, the response signal to the first wireless device, the first wireless device transmits, when the response signal is received, data to the second wireless device, and the second wireless device receives, after transmitting the response signal, the data from the first wireless device.Type: GrantFiled: June 5, 2019Date of Patent: January 10, 2023Assignee: Nippon Telegraph and Telephone CorporationInventors: Yosuke Fujino, Shigeru Teruhi, Kazunori Akabane
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Publication number: 20220417881Abstract: A synchronization method includes: a first step of transmitting a query command a plurality of times to a communication device configured to perform time synchronization with a base station device connected to a mobile communication network, the query command requesting time information expressed in a first unit, the first unit being lower in accuracy than accuracy of the time synchronization established by the communication device; a second step of determining timing at which the time information obtained in response to the query command is updated; a third step of determining timing to transmit a next query command, based on the timing at which the time information is updated; and a fourth step of acquiring time information with higher accuracy than the first unit, based on time information obtained in response to the query command transmitted at the third step.Type: ApplicationFiled: December 2, 2019Publication date: December 29, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shigeru TERUHI, Kento YOSHIZAWA, Kazunori AKABANE
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Publication number: 20220393778Abstract: A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.Type: ApplicationFiled: November 12, 2019Publication date: December 8, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yosuke FUJINO, Hiroyuki FUKUMOTO, Kazunori AKABANE
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Publication number: 20220353009Abstract: Provided is a radio communication system including a radio transmission apparatus including a plurality of transmission antennas and a radio reception apparatus including a plurality of reception antennas.Type: ApplicationFiled: September 27, 2019Publication date: November 3, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Marina NAKANO, Yosuke FUJINO, Hiroyuki FUKUMOTO, Kazunori AKABANE
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Publication number: 20220321182Abstract: A plurality of transmit antennas of a radio transmission device and a plurality of receive antennas of a radio reception device are located under the sea that is a line-of-sight environment, wherein the radio transmission device selects a frequency channel to be used based on an index value per frequency channel indicating orthogonality between the transmit and receive antennas defined based on a distance between the transmit and receive antennas and an angle indicating a direction of arrival of a radio signal, an interval between the plurality of transmit antennas, an interval between the plurality of receive antennas, and a modulation scheme, the distance between the transmit and receive antennas and the angle indicating the direction of arrival of the radio signal estimated by the radio reception device, and a desired bit error rate to be predetermined, selects the modulation scheme for providing a maximum transmission capacity per the selected frequency channel, separates transmission data into a pluralitType: ApplicationFiled: August 13, 2019Publication date: October 6, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Marina NAKANO, Yosuke FUJINO, Hiroyuki FUKUMOTO, Kazunori AKABANE
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Publication number: 20220271848Abstract: A communication device includes a channel estimation unit configured to estimate an impulse response based on signals of sound waves received by each of a plurality of hydrophones, a long delay removal unit configured to remove a long-delay impulse response from the impulse response to generate a post-removal impulse response, a weighting factor calculation unit configured to calculate a weighting factor based on the post-removal impulse response, and a synthesizing unit configured to synthesize the signals received by each of the plurality of hydrophones based on the weighting factor.Type: ApplicationFiled: July 1, 2019Publication date: August 25, 2022Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Hiroyuki FUKUMOTO, Yosuke FUJINO, Marina NAKANO, Kazunori AKABANE
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Patent number: 11411633Abstract: A transmission device includes a modulation unit that performs chirp-spread modulation on an input information series to generate a modulation signal; a delay unit that provides, to a plurality of modulation signals obtained by duplicating the modulation signal generated by the modulation unit, delays having lengths different from each other, a difference between the delays being an integral multiple of a reciprocal of a bandwidth of the modulation signal; and a plurality of transmission antennas that transmit the plurality of modulation signals, respectively, to which the delays are provided by the delay unit.Type: GrantFiled: February 1, 2019Date of Patent: August 9, 2022Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yosuke Fujino, Hiroyuki Fukumoto, Hajime Katsuda, Kazunori Akabane
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Publication number: 20220248340Abstract: An interference wave arithmetic operation method performed by a wireless communication system including a plurality of antennas, the method including: determining an interferer antenna on the basis of information regarding directivity, a position, and an orientation of each of the plurality of antennas; and calculating interference wave reception intensity of a victim antenna using an interference wave from the determined interferer antenna.Type: ApplicationFiled: April 6, 2020Publication date: August 4, 2022Inventors: Ryo Miyatake, Yusuke Asai, Daisei Uchida, Kazunori Akabane
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Patent number: 11368199Abstract: A reception unit in a radio communication apparatus receives wirelessly a signal configured with a preamble from another radio communication apparatus. The synchronization detection unit uses the preamble included in the signal received by the reception unit to detect synchronization with another radio communication apparatus. The signal accumulation unit accumulates a signal extracted from the signal received by the reception unit based on a timing at which the synchronization is detected by the synchronization detection unit. The combining unit combines the signals accumulated in the signal accumulation unit in accordance with a blind adaptive array antenna algorithm. The demodulation unit demodulates the signals combined by the combining unit.Type: GrantFiled: June 25, 2019Date of Patent: June 21, 2022Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Hajime Katsuda, Yosuke Fujino, Kazunori Akabane
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Publication number: 20220014278Abstract: An underwater acoustic communication system includes a transmission device including N transmitters, and a reception device. The reception device includes M (M is an integer of two or more) receivers configured to receive M reception signal sequences corresponding to N transmission signal sequences transmitted from the N transmitters through sound waves, a beam former configured to suppress multipath waves other than direct waves of the M received reception signal sequences and to generate L (L is an integer of two or more) signal sequences from the M reception signal sequences, and a signal estimation unit configured to estimate the N transmission signal sequences based on the L generated signal sequences.Type: ApplicationFiled: November 14, 2019Publication date: January 13, 2022Inventors: Yosuke Fujino, Hiroyuki FUKUMOTO, Marina NAKANO, Kazunori Akabane
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Publication number: 20210297124Abstract: A reception unit in a radio communication apparatus receives wirelessly a signal configured with a preamble from another radio communication apparatus. The synchronization detection unit uses the preamble included in the signal received by the reception unit to detect synchronization with another radio communication apparatus. The signal accumulation unit accumulates a signal extracted from the signal received by the reception unit based on a timing at which the synchronization is detected by the synchronization detection unit. The combining unit combines the signals accumulated in the signal accumulation unit in accordance with a blind adaptive array antenna algorithm. The demodulation unit demodulates the signals combined by the combining unit.Type: ApplicationFiled: June 25, 2019Publication date: September 23, 2021Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Hajime KATSUDA, Yosuke FUJINO, Kazunori AKABANE
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Patent number: 11115941Abstract: A time synchronization system includes a first wireless device and a second wireless device. A wireless unit of the first wireless device wirelessly transmits timing information and time information separately, the time information being acquired from a first clock and relating to a transmission time when the timing information was transmitted. A wireless unit of the second wireless device receives the wirelessly transmitted timing information and time information separately. A correction unit of the second wireless device corrects s a second clock on the basis of a reference time indicated by the second clock at a time when the wireless unit received the timing information, and a transmission time obtained from the time information.Type: GrantFiled: May 18, 2017Date of Patent: September 7, 2021Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shigeru Teruhi, Mamoru Kobayashi, Kazunori Akabane
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Publication number: 20210266832Abstract: To further reduce power consumption in a wireless communication device that performs intermittent operations.Type: ApplicationFiled: June 5, 2019Publication date: August 26, 2021Inventors: Yosuke Fujino, Shigeru Teruhi, Kazunori Akabane
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Publication number: 20210119685Abstract: A transmission device includes a modulation unit that performs chirp-spread modulation on an input information series to generate a modulation signal; a delay unit that provides, to a plurality of modulation signals obtained by duplicating the modulation signal generated by the modulation unit, delays having lengths different from each other, a difference between the delays being an integral multiple of a reciprocal of a bandwidth of the modulation signal; and a plurality of transmission antennas that transmit the plurality of modulation signals, respectively, to which the delays are provided by the delay unit.Type: ApplicationFiled: February 1, 2019Publication date: April 22, 2021Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yosuke FUJINO, Hiroyuki FUKUMOTO, Hajime KATSUDA, Kazunori AKABANE
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Publication number: 20190150106Abstract: A time synchronization system includes a first wireless device and a second wireless device. A wireless unit of the first wireless device wirelessly transmits timing information and time information separately, the time information being acquired from a first clock and relating to a transmission time when the timing information was transmitted. A wireless unit of the second wireless device receives the wirelessly transmitted timing information and time information separately. A correction unit of the second wireless device corrects s a second clock on the basis of a reference time indicated by the second clock at a time when the wireless unit received the timing information, and a transmission time obtained from the time information.Type: ApplicationFiled: May 18, 2017Publication date: May 16, 2019Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Shigeru TERUHI, Mamoru KOBAYASHI, Kazunori AKABANE
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Patent number: 9136893Abstract: A receiver includes a local signal generator, a power phase adjuster, and a frequency converter so as to perform frequency conversion on signals included in a plurality of radio frequency bands. The local signal generator supplies a plurality of local signals. The power phase adjuster adjusts local signals in terms of signal power or relative phases. The frequency converter performs frequency conversion on radio frequency bands by use of local signals adjusted with the power phase adjuster, thus sorting them in a desired frequency range.Type: GrantFiled: January 12, 2011Date of Patent: September 15, 2015Assignee: Nippon Telegraph and Telephone CorporationInventors: Takana Kaho, Yo Yamaguchi, Hiroyuki Shiba, Doohwan Lee, Takayuki Yamada, Kazunori Akabane, Kazuhiro Uehara