Patents by Inventor Ryuichi Ikematsu
Ryuichi Ikematsu 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: 10193651Abstract: It is difficult to improve the wavelength-band utilization rate of an optical network as a whole while operating the optical network stably; and therefore, an optical network controller according to an exemplary aspect of the present invention includes optical wavelength region setting means for setting a wavelength region in an optical transmission line between a plurality of optical nodes composing an optical network using wavelength division multiplexing system dividing the wavelength region into consecutive regions of a first wavelength region and a second wavelength region; optical path setting means for setting a first optical path in the first wavelength region and a second optical path in the second wavelength region, the second optical path differing from the first optical path in a route; and control unit for instructing the plurality of optical nodes on a central wavelength and a usable band of signal light for the optical node to transmit based on a setting by the optical path setting means.Type: GrantFiled: February 16, 2015Date of Patent: January 29, 2019Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Ryuichi Ikematsu, Akio Tajima, Tomoyuki Hino
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Patent number: 9609401Abstract: It is difficult to increase the number of inputs and outputs of an optical switch supporting CDC functions, therefore, an optical switch according to an exemplary aspect of the present invention includes a unit optical switch inputting n optical signals and outputting n optical signals; an optical splitter inputting a single optical signal, splitting the single optical signal into k optical signals, and outputting the k optical signals; and an optical selector inputting m optical signals and outputting a single optical signal, wherein the optical splitter includes m×n pieces, the unit optical switch includes m×k pieces, the optical selector includes n×k pieces, (k×(m×n)) outputs of the optical splitter correspond to (n×(m×k)) inputs of the unit optical switch, (n×(m×k)) outputs of the unit optical switch correspond to (m×(n×k)) inputs of the optical selector, and (n×m) optical signals inputted into the optical splitter are output through the (m×k) unit optical switch from the optical selector as (n×k) opticalType: GrantFiled: November 12, 2013Date of Patent: March 28, 2017Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Ryuichi Ikematsu, Akio Tajima
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Publication number: 20160352452Abstract: It is difficult to improve the wavelength-band utilization rate of an optical network as a whole while operating the optical network stably; and therefore, an optical network controller according to an exemplary aspect of the present invention includes optical wavelength region setting means for setting a wavelength region in an optical transmission line between a plurality of optical nodes composing an optical network using wavelength division multiplexing system dividing the wavelength region into consecutive regions of a first wavelength region and a second wavelength region; optical path setting means for setting a first optical path in the first wavelength region and a second optical path in the second wavelength region, the second optical path differing from the first optical path in a route; and control unit for instructing the plurality of optical nodes on a central wavelength and a usable band of signal light for the optical node to transmit based on a setting by the optical path setting means.Type: ApplicationFiled: February 16, 2015Publication date: December 1, 2016Applicant: NEC CorporationInventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Ryuichi IKEMATSU, Akio TAJIMA, Tomoyuki HINO
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Publication number: 20150289036Abstract: It is difficult to increase the number of inputs and outputs of an optical switch supporting CDC functions, therefore, an optical switch according to an exemplary aspect of the present invention includes a unit optical switch inputting n optical signals and outputting n optical signals; an optical splitter inputting a single optical signal, splitting the single optical signal into k optical signals, and outputting the k optical signals; and an optical selector inputting m optical signals and outputting a single optical signal, wherein the optical splitter includes m×n pieces, the unit optical switch includes m×k pieces, the optical selector includes n×k pieces, (k×(m×n)) outputs of the optical splitter correspond to (n×(m×k)) inputs of the unit optical switch, (n×(m×k)) outputs of the unit optical switch correspond to (m×(n×k)) inputs of the optical selector, and (n×m) optical signals inputted into the optical splitter are output through the (m×k) unit optical switch from the optical selector as (n×k) opticalType: ApplicationFiled: November 12, 2013Publication date: October 8, 2015Inventors: Hitoshi Takeshita, Ryuichi Ikematsu, Akio Tajima
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Patent number: 8693338Abstract: An exemplary object of the present invention lies in a point of providing a technology capable of measuring a transmission quality of an Ethernet network in order to utilize Ethernet as carrier-grade communication. The present invention includes an error bit number measurer for measuring the number of error bits that have occurred for a frame of Ethernet, being a target of monitoring, within a monitoring period, a transmitted bit number measurer for measuring the number of total transmitted bits of Ethernet frames that a device facing it has transmitted within the foregoing monitoring period, and a bit error rate operator for obtaining a bit error rate of a transmission path by employing a measurement result by the foregoing error bit number measurer and the foregoing transmitted bit number measurer.Type: GrantFiled: March 2, 2009Date of Patent: April 8, 2014Assignee: NEC CorporationInventors: Ryuichi Ikematsu, Hiroyuki Takagi, Kazuo Takagi, Zhenlong Cui
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Publication number: 20100220612Abstract: An exemplary object of the present invention lies in a point of providing a technology capable of measuring a transmission quality of an Ethernet network in order to utilize Ethernet as carrier-grade communication. The present invention includes an error bit number measurer for measuring the number of error bits that have occurred for a frame of Ethernet, being a target of monitoring, within a monitoring period, a transmitted bit number measurer for measuring the number of total transmitted bits of Ethernet frames that a device facing it has transmitted within the foregoing monitoring period, and a bit error rate operator for obtaining a bit error rate of a transmission path by employing a measurement result by the foregoing error bit number measurer and the foregoing transmitted bit number measurer.Type: ApplicationFiled: March 2, 2009Publication date: September 2, 2010Inventors: Ryuichi Ikematsu, Hiroyuki Takagi, Kazuo Takagi, Zhenlong Cui
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Publication number: 20080040081Abstract: In the simulation method of the present invention; one parameter is first selected from a plurality of parameters that relate to input/output characteristics. Next, regarding setting lines provided in a file for setting necessary choices from among a plurality of choices for a selected parameter, it is determined to either set choices by means of comment symbols that cause non-execution of the relevant lines, or set choices by means of identification codes, which are identifiers common to chips in which the same choice are to be set. When choices are to be set by means of comment symbols, the comment symbols of the setting lines of the necessary choices among the plurality of choices are deleted to make these setting lines effective. Alternatively, when choices are to be set by means of identification codes, the identification codes included in setting lines are rewritten to information for setting to the necessary choices. Finally, the simulation is executed.Type: ApplicationFiled: February 16, 2007Publication date: February 14, 2008Applicant: ELPIDA MEMORY, INC.Inventors: Yoji NISHIO, Seiji Funaba, Yurika Aoki, Kazuyoshi Shoji, Koji Matsuo, Mariko Otsuka, Ryuichi Ikematsu, Sadahiro Nonoyama, Kae Fujii
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Patent number: 7298694Abstract: To allow performance monitoring of the end-to-end path from the Ingress node to the Egress node of the GFP network by an FCS (Frame Check Sequence) check in a GFP (Generic Frame Procedure) frame, the FCS generation target area is set in the payload field of the GFP frame, no FCS recalculation is performed at the relay node and the GFP frame is transferred to the next node with the FCS added when the GFP frame is received even if an error is detected by the FCS check.Type: GrantFiled: December 20, 2001Date of Patent: November 20, 2007Assignee: NEC CorporationInventors: Satoshi Kamiya, Motoo Nishihara, Ryuichi Ikematsu
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Patent number: 6934295Abstract: In a multi-mode scheduler including a N×kM scheduler for adjusting data transmission between N-pieces of input interface sections and kM-pieces of output interface sections, the multi-mode scheduler, k-pieces of N×M schedulers to be the N×kM scheduler, and (k?1)-pieces of selection circuits for switching allocated output port information input from an outside of the N×kM scheduler and information from a N×M scheduler at front step, so as to be input to the N×M scheduler as allocated output port information, and two operations are set freely with a switching operation of the selection circuits. As a result, it is possible to provide a general scheduler.Type: GrantFiled: February 9, 2001Date of Patent: August 23, 2005Assignee: NEC CorporationInventor: Ryuichi Ikematsu
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Patent number: 6756898Abstract: Provided is a mode of alarm transfer for use in a system for transmitting an encapsulated Ethernet signal between an Ethernet termination device (110) connected to a terminal (100) and an Ethernet termination device (120) connected to a terminal (200) being disposed opposite to each other. The Ethernet termination device (110) detects notification form the Ethernet termination device (120) regarding a link down between the terminal (200) and the Ethernet termination device (120), or detects occurrence of a failure on a transmission path between the Ethernet termination device (110) and the Ethernet termination device (120). When a link between the terminal (100) and the Ethernet termination device (110) is disconnected forcibly based on the detection, notification to the Ethernet termination device (120) regarding the link down between the terminal (100) and the Ethernet termination device (110) is withheld.Type: GrantFiled: September 18, 2002Date of Patent: June 29, 2004Assignee: NEC CorporationInventor: Ryuichi Ikematsu
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Patent number: 6731636Abstract: In a scheduler having m input interfaces and n output interfaces in an ATM switching apparatus, each of m and n is an integer equal to or more than 2. The scheduler is includes a storage unit, first and second rearranging unit, a control unit and a searching unit. The storage unit stores a plurality of shuffle patterns including first to fourth shuffle patterns. The first rearranging unit carries out a first shuffling operation in units of k data (k is an integer equal to or more than 2 and less than or equal to s which is one of n and m, the other being t) and a second shuffling operation in units of u groups (u is an integer equal to or more than 2 and corresponding to s/k) to (m×n) data supplied from the m input interfaces based on the first and second shuffle patterns to produce first rearranged data. The (m×n) data are grouped into (t×u) groups.Type: GrantFiled: October 2, 2000Date of Patent: May 4, 2004Assignee: NEC CorporationInventor: Ryuichi Ikematsu
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Publication number: 20030058106Abstract: Provided is a mode of alarm transfer for use in a system for transmitting an encapsulated Ethernet signal between an Ethernet termination device (110) connected to a terminal (100) and an Ethernet termination device (120) connected to a terminal (200) being disposed opposite to each other. The Ethernet termination device (110) detects notification form the Ethernet termination device (120) regarding a link down between the terminal (200) and the Ethernet termination device (120), or detects occurrence of a failure on a transmission path between the Ethernet termination device (110) and the Ethernet termination device (120). When a link between the terminal (100) and the Ethernet termination device (110) is disconnected forcibly based on the detection, notification to the Ethernet termination device (120) regarding the link down between the terminal (100) and the Ethernet termination device (110) is withheld.Type: ApplicationFiled: September 18, 2002Publication date: March 27, 2003Applicant: NEC CorporationInventor: Ryuichi Ikematsu
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Patent number: 6535479Abstract: A hitless switching system in an asynchronous transfer mode (ATM) apparatus, includes a first system switch section and a second system switch section. The first system switch section has a first cell buffer, and sequentially stores a sequence of cells in the first cell buffer to sequentially output the stored cells from the first cell buffer while performing a discard priority control to the sequence of cells. Also, the first system switch section stops the discard priority control when a switching control cell is detected in the sequence of cells. The second system switch section has a second cell buffer, and sequentially stores the input cells in the second cell buffer to sequentially output the stored cells from the second cell buffer while performing the discard priority control to the sequence of cells.Type: GrantFiled: November 23, 1998Date of Patent: March 18, 2003Assignee: NEC CorporationInventor: Ryuichi Ikematsu
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Patent number: 6490282Abstract: A switching control cell is inserted into an input cell in a switching control cell generator. In a period between the detection of a switching control cell in a first or second switching control cell detector and the detection of the switching control cell in a third switching control cell detector, in active and stand-by switches, when a cell is discarded in any one of the active and stand-by switches, in addition to priority discard control, the same cell is discarded in the other switch independently of the priority discard control. Further, upon detection of a switching control cell in the switching control cell detector, all the cells accumulated within the cell buffer are discarded, and until the detection of the switching control cell in the switching control cell detector, reading from the cell buffer is stopped so that the same cell is written into the cell buffer in the active switch and the cell buffer in the stand-by switch.Type: GrantFiled: March 12, 1999Date of Patent: December 3, 2002Assignee: NEC CorporationInventor: Ryuichi Ikematsu
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Publication number: 20020090007Abstract: To allow performance monitoring of the end-to-end path from the Ingress node to the Egress node of the GFP network by an FCS (Frame Check Sequence) check in a GFP (Generic Frame Procedure) frame, the FCS generation target area is set in the payload field of the GFP frame, no FCS recalculation is performed at the relay node and the GFP frame is transferred to the next node with the FCS added when the GFP frame is received even if an error is detected by the FCS check.Type: ApplicationFiled: December 20, 2001Publication date: July 11, 2002Inventors: Satoshi Kamiya, Motoo Nishihara, Ryuichi Ikematsu
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Publication number: 20010014098Abstract: In a multi-mode scheduler including a N×kM scheduler for adjusting data transmission between N-pieces of input interface sections and kM-pieces of output interface sections, the multi-mode scheduler, k-pieces of N×M schedulers to be the N×kM scheduler, and (k−1)-pieces of selection circuits for switching allocated output port information input from an outside of the N×kM scheduler and information from a N×M scheduler at front step, so as to be input to the N×M scheduler as allocated output port information, and two operations are set freely with a switching operation of the selection circuits. As a result, it is possible to provide a general scheduler.Type: ApplicationFiled: February 9, 2001Publication date: August 16, 2001Inventor: Ryuichi Ikematsu
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Patent number: 5440565Abstract: In a test method and apparatus for testing a virtual path in an asynchronous transfer mode system, a sequence number is included in an operation administrating monitoring (OAM) cell to specify the OAM cell for testing a virtual path between transmission and reception sides. The sequence number is inserted into the OAM cell by the use of an idle cell and is received by a sequence number test circuit included in the reception side. The sequence number in the OAM is collated with a result of counting the OAM cell in the reception side to detect coincidence or non-coincidence between the sequence number and the result of counting. On detecting the non-coincidence, a loss of the OAM cell or wrong reception of the OAM cell is detected on the reception side. Otherwise normal operation is confirmed between the transmission and the reception sides.Type: GrantFiled: June 13, 1994Date of Patent: August 8, 1995Assignee: NEC CorporationInventors: Akihiro Miyamoto, Ryuichi Ikematsu, Haruhiko Matsunaga, Hiromi Ueda
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Patent number: 5359600Abstract: In an ATM switching network, ATM (asynchronous transfer mode) self-routing switches are interconnected by facilities carrying STM-N (synchronous transport modules level N) signals. At each inlet of an ATM self-routing switch, an STM overhead is removed from each frame of an incoming STM-N signal to create a vacant interval and the frame is converted according to ATM cell format into a series of data ATM cells, and an idle ATM cell is derived from the vacant interval. A supervisory bit sequence is inserted to the payload field of the idle ATM cell to produce a supervisory ATM cell, and the data and supervisory ATM cells are sent into the ATM switch. At each outlet of the switch, the bit sequence of the supervisory ATM cell is checked to evaluate the quality of the ATM switch and a series of data ATM cells is then converted into an STM-N signal according to STM-N frame format.Type: GrantFiled: February 16, 1993Date of Patent: October 25, 1994Assignees: Nippon Telegraph and Telephone Corporation, NEC Corporation, Hitachi, Ltd., Fujitsu LimitedInventors: Hiromi Ueda, Kenji Akutsu, Ryuichi Ikematsu, Takatoshi Kurano, Yoshihiro Ashi, Yukio Nakano, Takafumi Chujo, Shigeo Amemiya