Patents by Inventor Osamu Kurokawa
Osamu Kurokawa 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: 11927923Abstract: A management apparatus in a time synchronization system includes a time variation information receiving unit configured to acquire time variation information and position information of a time synchronization apparatus, a position information classifying unit configured to classify time synchronization apparatuses into predetermined categories based on the acquired position information, a time variation analysis configured to determine majority based on whether patterns of time variation of the time synchronization apparatuses belonging to an identical category are identical to each other, and to analyze the time variation based on the determined results, and a filtering and delivery unit configured to output an instruction to block the time information received from the positioning satellite, to the time synchronization apparatus having abnormal time variation.Type: GrantFiled: March 5, 2019Date of Patent: March 12, 2024Assignee: Nippon Telegraph and Telephone CorporationInventors: Takaaki Hisashima, Hiroki Sakuma, Kaoru Arai, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Patent number: 11815552Abstract: [Problem] To monitor a frequency difference between an input clock and a synchronous clock synchronized with the input clock. [Solution] A clock frequency monitoring apparatus that monitors the frequency of an input clock 18a includes a phase comparator 12 that compares a phase of a synchronous clock 18e phase-synchronized with the input clock 18a or a first frequency-divided clock 18f obtained by frequency-dividing the synchronous clock 18e with the phase of the input clock 18a, a filter 13 that low-pass filters an output signal of the phase comparator 12, an oscillator 14 that generates the synchronous clock 18e having a frequency corresponding to a control value from the filter 13, and a determiner 19 that determines that the frequency of the input clock 18a is abnormal when the variation amplitude of the output signal of the filter 13 is equal to or more than a predetermined range.Type: GrantFiled: July 16, 2019Date of Patent: November 14, 2023Assignee: Nippon Telegraph and Telephone CorporationInventors: Takaaki Hisashima, Hiroki Sakuma, Kaoru Arai, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Patent number: 11240141Abstract: [Problem] To select an optimal transmission path having a minimum total MTIE value of total MTIE values between a plurality of master apparatuses configured to transmit time information serving as a reference and a specific relay apparatus configured to receive the time information via a plurality of relay apparatuses to achieve time synchronization. [Solution] A time path selection apparatus 30 selects a transmission path employed for time synchronization, on the basis of a MTIE value evaluated in each of relay apparatuses 13 to 16, between master apparatuses 11 and 12 configured to transmit time information serving as a reference and a relay apparatus 15 or 16 at an edge configured to receive the time information via a relay apparatus 13 or 14 to achieve the time synchronization.Type: GrantFiled: February 15, 2019Date of Patent: February 1, 2022Assignee: Nippon Telegraph and Telephone CorporationInventors: Ryuta Sugiyama, Kaoru Arai, Hiroki Sakuma, Takaaki Hisashima, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Patent number: 11196499Abstract: [Problem] It is possible to improve the quality of time information by suppressing a jump in time which arises when switching a transfer path in a BC apparatus to which transfer paths of time information of at least 2 systems are connected to an input side. [Solution] A time synchronization apparatus 20 is mounted on a BC apparatus 12c in which two systems of at least a 0-system route (0-system) and a 1-system route (1-system) are connected to an input side, and includes a time correction value holding unit 26 configured to hold a 0-system correction value in which a time error resulting from delay of UTC due to performance inherent to the BC apparatus is the same value as a time error accumulated on the 0-system side and a 1-system correction value in which the time error is the same value as a time error accumulated on the 1-system side.Type: GrantFiled: March 4, 2019Date of Patent: December 7, 2021Assignee: Nippon Telegraph and Telephone CorporationInventors: Kaoru Arai, Hiroki Sakuma, Takaaki Hisashima, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Patent number: 11196535Abstract: A local device of a time synchronization system includes a path switching unit that connects respective remote devices using individual optical fibers and switches the respective optical fibers sequentially in a cyclic order, a counter unit, a phase difference memory unit, and a table unit. The counter unit counts a pulse signal P1d demodulated by a PPS demodulation unit to obtain a count value. The phase difference memory unit stores the count value as path information in association with a phase difference detected by a phase detection unit, and outputs the phase difference associated with this path information indicated by the count value to the variable delay unit. When the count value is input, the table unit outputs a path switching signal for switching to the next optical fiber in the cyclic order to the path switching unit and the path switching unit performs switching to the next optical fiber.Type: GrantFiled: July 17, 2019Date of Patent: December 7, 2021Assignee: Nippon Telegraph and Telephone CorporationInventors: Hiroki Sakuma, Kaoru Arai, Takaaki Hisashima, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Patent number: 11196533Abstract: [Problem] To synchronize timings of transmitting and receiving a pulse signal (1 PPS signal) at a constant interval between communication apparatuses even in a case where an optical fiber connecting the communication apparatuses fluctuates in an optical characteristic and an optical fiber length. [Solution] The time synchronization system 20 transmits and receives a pulse signal at a constant interval between a local apparatus L (apparatus L) and a remote apparatus R (apparatus R) connected through the two-core bidirectional optical fibers F1 and F2 to synchronize time.Type: GrantFiled: February 15, 2019Date of Patent: December 7, 2021Assignee: Nippon Telegraph and Telephone CorporationInventors: Hiroki Sakuma, Kaoru Arai, Ryuta Sugiyama, Takaaki Hisashima, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Publication number: 20210314134Abstract: [Problem] To reduce a total equipment cost. [Solution] A local device (20A) of a time synchronization system (10A) includes a path switching unit (33) that connects respective remote devices (40A1 to 40An) using individual optical fibers (60a to 60n) and switches the respective optical fibers (60a to 60n) sequentially in a cyclic order, a counter unit (31), a phase difference memory unit (30), and a table unit (32). The counter unit (31) counts a pulse signal P1d demodulated by a PPS demodulation unit (23) to obtain a count value (T1). The phase difference memory unit (30) stores the count value (T1) as path information in association with a phase difference (?1) detected by a phase detection unit (22), and outputs, when the count value (T1) is input, the phase difference (?1) associated with this path information indicated by the count value (T1) to the variable delay unit (24).Type: ApplicationFiled: July 17, 2019Publication date: October 7, 2021Inventors: Hiroki Sakuma, Kaoru Arai, Takaaki Hisashima, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Publication number: 20210302499Abstract: [Problem] To monitor a frequency difference between an input clock and a synchronous clock synchronized with the input clock. [Solution] A clock frequency monitoring apparatus that monitors the frequency of an input clock 18a includes a phase comparator 12 that compares a phase of a synchronous clock 18e phase-synchronized with the input clock 18a or a first frequency-divided clock 18f obtained by frequency-dividing the synchronous clock 18e with the phase of the input clock 18a, a filter 13 that low-pass filters an output signal of the phase comparator 12, an oscillator 14 that generates the synchronous clock 18e having a frequency corresponding to a control value from the filter 13, and a determiner 19 that determines that the frequency of the input clock 18a is abnormal when the variation amplitude of the output signal of the filter 13 is equal to or more than a predetermined range.Type: ApplicationFiled: July 16, 2019Publication date: September 30, 2021Inventors: Takaaki HISASHIMA, Hiroki SAKUMA, Kaoru ARAI, Ryuta SUGIYAMA, Shunichi TSUBOI, Osamu KUROKAWA, Kazuyuki MATSUMURA
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Publication number: 20210072707Abstract: A management apparatus in a time synchronization system includes a time variation information receiving unit configured to acquire time variation information and position information of a time synchronization apparatus, a position information classifying unit configured to classify time synchronization apparatuses into predetermined categories based on the acquired position information, a time variation analysis configured to determine majority based on whether patterns of time variation of the time synchronization apparatuses belonging to an identical category are identical to each other, and to analyze the time variation based on the determined results, and a filtering and delivery unit configured to output an instruction to block the time information received from the positioning satellite, to the time synchronization apparatus having abnormal time variation.Type: ApplicationFiled: March 5, 2019Publication date: March 11, 2021Inventors: Takaaki Hisashima, Hiroki Sakuma, Kaoru Arai, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Publication number: 20210058223Abstract: [Problem] To synchronize timings of transmitting and receiving a pulse signal (1 PPS signal) at a constant interval between communication apparatuses even in a case where an optical fiber connecting the communication apparatuses fluctuates in an optical characteristic and an optical fiber length. [Solution] The time synchronization system 20 transmits and receives a pulse signal at a constant interval between a local apparatus L (apparatus L) and a remote apparatus R (apparatus R) connected through the two-core bidirectional optical fibers F1 and F2 to synchronize time.Type: ApplicationFiled: February 15, 2019Publication date: February 25, 2021Inventors: Hiroki SAKUMA, Kaoru ARAI, Ryuta SUGIYAMA, Takaaki HISASHIMA, Shunichi TSUBOI, Osamu KUROKAWA, Kazuyuki MATSUMURA
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Publication number: 20210021362Abstract: [Problem] It is possible to improve the quality of time information by suppressing a jump in time which arises when switching a transfer path in a BC apparatus to which transfer paths of time information of at least 2 systems are connected to an input side. [Solution] A time synchronization apparatus 20 is mounted on a BC apparatus 12c in which two systems of at least a 0-system route (0-system) and a 1-system route (1-system) are connected to an input side, and includes a time correction value holding unit 26 configured to hold a 0-system correction value in which a time error resulting from delay of UTC due to performance inherent to the BC apparatus is the same value as a time error accumulated on the 0-system side and a 1-system correction value in which the time error is the same value as a time error accumulated on the 1-system side.Type: ApplicationFiled: March 4, 2019Publication date: January 21, 2021Inventors: Kaoru Arai, Hiroki Sakuma, Takaaki Hisashima, Ryuta Sugiyama, Shunichi Tsuboi, Osamu Kurokawa, Kazuyuki Matsumura
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Publication number: 20200403901Abstract: [Problem] To select an optimal transmission path having a minimum total MTIE value of total MTIE values between a plurality of master apparatuses configured to transmit time information serving as a reference and a specific relay apparatus configured to receive the time information via a plurality of relay apparatuses to achieve time synchronization. [Solution] A time path selection apparatus 30 selects a transmission path employed for time synchronization, on the basis of a MTIE value evaluated in each of relay apparatuses 13 to 16, between master apparatuses 11 and 12 configured to transmit time information serving as a reference and a relay apparatus 15 or 16 at an edge configured to receive the time information via a relay apparatus 13 or 14 to achieve the time synchronization.Type: ApplicationFiled: February 15, 2019Publication date: December 24, 2020Inventors: Ryuta SUGIYAMA, Kaoru ARAI, Hiroki SAKUMA, Takaaki HISASHIMA, Shunichi TSUBOI, Osamu KUROKAWA, Kazuyuki MATSUMURA
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Patent number: 9900818Abstract: When a representative PS server receives a P-TMSI contained in a PDP context succession request signal from a UE according to a handover communication procedure prescribed in an applicable standard after the UE moves, if the PS server identified with the identification information contained in the received P-TMSI is not its own representative PS server, the representative PS server identifies the PS server identified with the identification information as a PS server that manages a femtocell base station to which the UE belonged before it moved and forwards the PDP context succession request signal to the identified PS server.Type: GrantFiled: August 28, 2012Date of Patent: February 20, 2018Assignee: NEC CorporationInventors: Yusuke Miyagawa, Takayuki Kido, Takuo Akimoto, Yuki Nakanishi, Osamu Kurokawa, Yasuhiro Watanabe
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Patent number: 9609494Abstract: When a femto cell base station used for a communication system provided with a function of providing a predetermined supplementary service receives first information indicating supplementary service control from a radio terminal, the femto cell base station converts the received information to a SIP (Session Initiation Protocol) message including the first information and transmits the SIP message to a higher apparatus in the communication system.Type: GrantFiled: March 27, 2015Date of Patent: March 28, 2017Assignee: NEC CORPORATIONInventors: Osamu Kurokawa, Kazuki Eguchi, Naoki Yoshida, Shunsuke Yokouchi, Toru Shiiba, Tomiharu Hamaguchi, Yasuyuki Ueda, Yasuhiro Watanabe, Hiroaki Akiyama, Takayuki Kido
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Patent number: 9532292Abstract: When a representative service control device receives a PDP context succession request signal according to a handover communication procedure prescribed in an applicable standard, the representative service control device transmits a P-TMSI contained in the PDP context succession request signal as an address request to a database device. When the representative service control device receives address information of a service control device from the database device, the representative service control device forwards the PDP context succession request signal received from the request transmission means to the received address.Type: GrantFiled: August 27, 2012Date of Patent: December 27, 2016Assignee: NEC CorporationInventors: Yusuke Miyagawa, Takayuki Kido, Takuo Akimoto, Osamu Kurokawa, Yuki Nakanishi, Yasuhiro Watanabe
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Patent number: 9264882Abstract: In order to enable a communication system introduced with a femtocell base station using an IMS network, to perform PS service similar to that of the existing 3G network, a service control apparatus (SGSN functional unit), based on the UE's message transmitted to the femtocell base station (FAP), acquires UE's subscriber information for PS (Packet Switching) service, from a HLR and registers the subscriber information in a VLR that is present on the IMS network. Then, service control apparatus performs PS service based on the subscriber information registered in the VLR.Type: GrantFiled: June 22, 2012Date of Patent: February 16, 2016Assignee: NEC CORPORATIONInventors: Yusuke Miyagawa, Takayuki Kido, Takuo Akimoto, Osamu Kurokawa, Yuki Nakanishi, Yasuhiro Watanabe
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Patent number: 9215576Abstract: A communication system of the present invention is a communication system connected to a public communication network including emergency organization communication apparatus (14), the communication system includes femto base station (2) wirelessly connected to wireless terminal (1), wherein femto base station (2) includes a first communication controller that attaches first location information, which is information for identifying a location of femto base station (2) or for identifying a location of an assembly of a plurality of base stations including femto base station (2), to a SIP message in order to notify the first location information to emergency organization communication apparatus (14) when there is a call from wireless terminal (1), and transmits the SIP message to another apparatus.Type: GrantFiled: December 21, 2009Date of Patent: December 15, 2015Assignee: NEC CORPORATIONInventors: Osamu Kurokawa, Kazuki Eguchi, Naoki Yoshida, Shunsuke Yokouchi, Yasuhiro Watanabe, Hiroaki Akiyama, Takuo Akimoto
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Patent number: 9191387Abstract: A femto cell base station includes a generating part that generates a SIP message including a terminal ID of a radio terminal and a check request for the terminal ID at a predetermined time, and a first transmitting part that transmits the SIP message generated by the generating part to a higher level apparatus in the communication system.Type: GrantFiled: July 20, 2010Date of Patent: November 17, 2015Assignee: NEC CORPORATIONInventors: Osamu Kurokawa, Kazuki Eguchi, Naoki Yoshida, Shunsuke Yokouchi, Toru Shiiba, Yasuyuki Ueda, Tomiharu Hamaguchi, Yasuhiro Watanabe, Hiroaki Akiyama, Takayuki Kido
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Patent number: 9088880Abstract: A femtocell base station (FAP) converts, when information concerning a SMS is received from UE (User Equipment), the received information concerning the SMS into a SIP (Session Initiation Protocol) message including the received information concerning the SMS and transmits the converted SIP message to the core network side. The femtocell base station converts, when a SIP message including information concerning the SMS is received from the core network side, the information concerning the SMS included in the received SIP message into a message that can be recognized by the UE and transmits the converted information concerning the SMS to the UE.Type: GrantFiled: June 30, 2010Date of Patent: July 21, 2015Assignee: NEC CORPORATIONInventors: Osamu Kurokawa, Kazuki Eguchi, Naoki Yoshida, Shunsuke Yokouchi, Toru Shiiba, Yasuyuki Ueda, Tomiharu Hamaguchi, Yasuhiro Watanabe, Hiroaki Akiyama, Takayuki Kido
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Publication number: 20150201315Abstract: When a femto cell base station used for a communication system provided with a function of providing a predetermined supplementary service receives first information indicating supplementary service control from a radio terminal, the femto cell base station converts the received information to a SIP (Session Initiation Protocol) message including the first information and transmits the SIP message to a higher apparatus in the communication system.Type: ApplicationFiled: March 27, 2015Publication date: July 16, 2015Applicant: NEC CORPORATIONInventors: Osamu KUROKAWA, Kazuki EGUCHI, Naoki YOSHIDA, Shunsuke YOKOUCHI, Toru SHIIBA, Tomiharu HAMAGUCHI, Yasuyuki UEDA, Yasuhiro WATANABE, Hiroaki AKIYAMA, Takayuki KIDO