Patents by Inventor Yasuhiko Matsunaga

Yasuhiko Matsunaga 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).

  • Patent number: 8498155
    Abstract: A nonvolatile semiconductor memory device includes a substrate including device regions extending in a first direction, a memory cell array region including a plurality of memory cells disposed on the device regions, bit lines extending in the first direction, a sense amplifier circuit connected to ends of the bit lines, and bit line contacts connecting device regions to bit lines. The memory cell array region includes first to N-th regions where N is an integer of two or more, and a K-th region is located at a greater distance from the sense amplifier circuit than a (K?1)-th region, where K is an arbitrary integer of 2 to N. Contact resistance of the bit line contacts in the K-th region is lower than contact resistance of the bit line contacts in the (K?1)-th region, each device region having constant width in the memory cell array region.
    Type: Grant
    Filed: October 20, 2011
    Date of Patent: July 30, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yasuhiko Matsunaga
  • Publication number: 20130157680
    Abstract: In order to effectively determine an optimized radio resource, a radio communication system (100) includes a plurality of first base stations (111) and a plurality of first mobile stations (112) respectively connected to the plurality of first base stations (111). In the radio communication system (100), there are included calculation means (103) for calculating a statistic (130) by aggregating interference levels of radio waves between the plurality of first base stations (111) and second mobile stations (122) connected to a second base station (121) that forms a second cell (120) larger than a first cell (110) formed by each of the first base stations (111); and determination means (104) for determining, based on the statistic (130), a radio resource to be used by the plurality of first base stations (111) or the plurality of first mobile stations (112).
    Type: Application
    Filed: August 17, 2011
    Publication date: June 20, 2013
    Applicant: NEC CORPORATION
    Inventors: Motoki Morita, Kojiro Hamabe, Yasuhiko Matsunaga
  • Publication number: 20130137473
    Abstract: The present invention is applicable to a wireless communication system provided with mobile terminals and base stations that manage cells to which the mobile terminals are connected. The wireless communication system of the present invention has a new cell detection unit that detects, from among neighbor cells which are adjacent to the cells to which the mobile terminals are connected, new cells that have newly started or whose operation has resumed or whose geographical range has changed, and a neighbor cell list generation unit which preferentially registers new cells that have been detected by the new cell detection unit in neighbor cell lists in which are registered neighbor cells that are candidates for handover destinations of the mobile terminals.
    Type: Application
    Filed: August 3, 2011
    Publication date: May 30, 2013
    Applicant: NEC CORPORATION
    Inventors: Yoshinori Watanabe, Yasuhiko Matsunaga, Kojiro Hamabe
  • Publication number: 20130102321
    Abstract: Terminals and base stations belonging to service areas of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link to notify them to a radio-resource management server. The server alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduces interference with a neighboring radio system. When a load is concentrated on a network of a specific radio operator, handover instruction is given to the terminal from the server to realize a load distribution. When the server detects excessive radio interference between the radio operators, it notifies occurrence of a fault, an interference quantity, a quantity of the transmitted power that the base station should attenuate, and the frequency that the base station should alter to the radio operator that becomes an interference source.
    Type: Application
    Filed: October 10, 2012
    Publication date: April 25, 2013
    Applicant: NEC Corporation
    Inventor: Yasuhiko Matsunaga
  • Patent number: 8428520
    Abstract: Provided is a technique of calculating a proper margin according to the area or a radio propagation estimation method in the area design of wireless communication using a radio propagation simulator. From a storage part wherein information relating to positions where deterioration of a communication quality or a radio quality is confirmed and information relating to the radio conditions at the positions are associated with each other, a margin design system extracts positions where the radio conditions are equal, estimates the radio quality at the positions by the radio propagation simulator, and calculates the margin of a radio quality estimated value on the basis of the estimated radio quality.
    Type: Grant
    Filed: March 18, 2009
    Date of Patent: April 23, 2013
    Assignee: NEC Corporation
    Inventors: Kosei Kobayashi, Yasuhiko Matsunaga, Yoshinori Watanabe
  • Patent number: 8315631
    Abstract: Terminals and base stations belonging to service areas 100 to 102 of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link to notify them to a radio-resource management server 40. The server 40 alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduces interference with a neighboring radio system. When a load is concentrated on a network of a specific radio operator, an instruction of handover is given to the terminal from the server 40 to realize a load distribution within the radio operator, and between the radio operators.
    Type: Grant
    Filed: September 15, 2010
    Date of Patent: November 20, 2012
    Assignee: NEC Corporation
    Inventor: Yasuhiko Matsunaga
  • Publication number: 20120201159
    Abstract: A base station includes a radio communication unit, a resource adjustment unit, a resource division unit and a detection unit. The resource adjustment unit determines radio resources to be allocated to a downlink communication from a radio resource region shared with another base station. The resource division unit limits, to a first radio resource segment which is a part of the radio resource region, radio resources in response to estimating that communication quality of the downlink communication using the limited first radio resource segment is improved over the communication quality of the first downlink communication when using the entire range of the radio resource region that is shared with the other base station. The detection unit detects execution of resource division by the other base station for limiting radio resources used for another downlink communication between the other base station and a mobile station to a second radio resource segment.
    Type: Application
    Filed: February 3, 2012
    Publication date: August 9, 2012
    Applicant: NEC CORPORATION
    Inventors: Motoki MORITA, Yasuhiko MATSUNAGA
  • Patent number: 8179720
    Abstract: A NAND flash memory includes a NAND string and a control circuit, wherein in a write operation, the control circuit applies a writing voltage between a control gate of a selected memory cell to be written and a semiconductor well, and after the write operation and before performing a verification read operation of verifying whether data has been written into the selected memory cell, the control circuit performs a de-trapping operation, in which a first voltage of a same potential as that of the semiconductor well or a same polarity as that of the writing voltage is applied to the control gate of the selected memory cell and in which a second voltage of a same polarity as that of the writing voltage and larger than the first voltage as an absolute value is applied to a control gate of unselected memory cells not to be written.
    Type: Grant
    Filed: March 19, 2010
    Date of Patent: May 15, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Fukuda, Yasuhiko Matsunaga
  • Patent number: 8169927
    Abstract: A configuration of a wireless cell contained by a wireless network control station in a wireless access network is optimized to efficiently achieve leveling of a processing load in the wireless network control station. A wireless access network management device inputs input information including position information of a wireless cell, traffic demand of each wireless cell, location registration demand of each wireless cell, handover demand with respect to each adjacent wireless cells of each wireless cell, and internal processing time required by a wireless network control station for traffic processing, location registration processing, and handover processing. Then, a wireless cell group to be controlled by a wireless network control station is selected based on the input information so that processing loads of a plurality of wireless network control station are leveled.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: May 1, 2012
    Assignee: NEC Corporation
    Inventor: Yasuhiko Matsunaga
  • Publication number: 20120099374
    Abstract: A nonvolatile semiconductor memory device includes a substrate including device regions extending in a first direction, a memory cell array region including a plurality of memory cells disposed on the device regions, bit lines extending in the first direction, a sense amplifier circuit connected to ends of the bit lines, and bit line contacts connecting device regions to bit lines. The memory cell array region includes first to N-th regions where N is an integer of two or more, and a K-th region is located at a greater distance from the sense amplifier circuit than a (K?1)-th region, where K is an arbitrary integer of 2 to N. Contact resistance of the bit line contacts in the K-th region is lower than contact resistance of the bit line contacts in the (K?1)-th region, each device region having constant width in the memory cell array region.
    Type: Application
    Filed: October 20, 2011
    Publication date: April 26, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Yasuhiko MATSUNAGA
  • Publication number: 20120083281
    Abstract: A network management system includes: wireless link quality information collection means for collecting, from a mobile terminal that is connected to the mobile communication network, wireless link quality information that indicates wireless link quality measured by the mobile terminal, the wireless link quality information containing information about quality of wireless links between the mobile terminal and two or more wireless cells; coverage evaluation means for evaluating the wireless cell coverage on the basis of wireless link quality information calculated for each of the wireless cells using the wireless link quality information collected by the wireless link quality information collection means; and wireless parameter calculation means for calculating an amount of change in changing for a wireless parameter of a wireless base station on the basis of the result of the evaluation provided by the coverage evaluation means.
    Type: Application
    Filed: April 14, 2010
    Publication date: April 5, 2012
    Applicant: NEC Corporation
    Inventors: Yoshinori Watanabe, Yasuhiko Matsunaga
  • Publication number: 20120063317
    Abstract: To provide a base station in which an electric power consumed in the base station can be suppressed and an electromagnetic wave interference between the base stations can be avoided, a method for controlling a base station, a control program, and a mobile station. The base station includes storage means, traffic history generation means for measuring a traffic of the base station for each unit time and storing it in the storage means as a traffic history, and control means for controlling transmission of a control signal based on the traffic history.
    Type: Application
    Filed: March 15, 2010
    Publication date: March 15, 2012
    Applicant: NEC CORPORATION
    Inventors: Kazushi Muraoka, Yasuhiko Matsunaga, Masayuki Ariyoshi, Toshifumi Nakamura
  • Patent number: 8134198
    Abstract: A nonvolatile semiconductor memory includes active regions . . . AAj?1, AAj, AAj?1, . . . formed in a semiconductor substrate; a plurality of word lines WL0, WL1, . . . in the row direction; memory cell transistors, each including a floating gate provided on the semiconductor substrate via a tunneling insulating film, an inter-gate insulating film disposed on the floating gate, and a control gate disposed on the inter-gate insulating film, disposed on intersections of word lines and active regions; select gate lines SGD in the row direction; bit line contacts CB disposed on the active regions; and a plurality of bit lines in the column direction and connected to the active regions via the bit line contacts; and the bit line contacts are formed by forming an electrode material for the bit line contacts in lines in the row direction and cutting the electrode material for each of the bit lines to avoid contact-failure of bit line contacts CB.
    Type: Grant
    Filed: November 24, 2006
    Date of Patent: March 13, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Kamigaichi, Yasuhiko Matsunaga
  • Publication number: 20120037976
    Abstract: A nonvolatile semiconductor memory includes a memory cell transistor including a first floating gate electrode layer formed on a first tunneling insulating film, a first inter-gate insulating film, first and second control gate electrode layers, and a first metallic silicide film; a high voltage transistor including a high voltage gate electrode layer formed on a high voltage gate insulating film, a second inter-gate insulating film having an aperture, third and fourth control gate electrode layers, and a second metallic silicide film; a low voltage transistor including a second floating gate electrode layer formed on a second tunneling insulating film, a third inter-gate insulating film having an aperture, fifth and sixth control gate electrode layers, and a third metallic silicide film; and a liner insulating film directly disposed on source and drain regions of each of the memory cell transistor, the low voltage transistor, and the high voltage transistor.
    Type: Application
    Filed: September 19, 2011
    Publication date: February 16, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kikuko Sugimae, Masayuki Ichige, Fumitaka Arai, Yasuhiko Matsunaga, Atsuhiro Sato
  • Patent number: 8103220
    Abstract: Terminals and base stations belonging to service areas 100 to 102 of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link to notify them to a radio-resource management server 40. The server 40 alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduces interference with a neighboring radio system. When a load is concentrated on a network of a specific radio operator, an instruction of handover is given to the terminal from the server 40 to realize a load distribution within the radio operator, and between the radio operators.
    Type: Grant
    Filed: September 15, 2010
    Date of Patent: January 24, 2012
    Assignee: NEC Corporation
    Inventor: Yasuhiko Matsunaga
  • Patent number: 8098527
    Abstract: A semiconductor memory device includes a semiconductor substrate; a memory cell array on the semiconductor substrate, the memory cell array comprising a plurality of memory cells capable of electrically storing data; a sense amplifier configured to detect the data stored in at least one of the memory cells; a cell source driver electrically connected to source side terminals of the memory cells and configured to supply a source potential to at least one of the source side terminals of the memory cells; a first wiring configured to electrically connect between at least one of the source side terminals of the memory cells and the cell source driver; and a second wiring formed in a same wiring layer as the first wiring, the second wiring being insulated from the first wiring and being electrically connected to the sense amplifier, wherein the first wiring and the second wiring have a plurality of through holes provided at a predetermined interval.
    Type: Grant
    Filed: December 30, 2009
    Date of Patent: January 17, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Fukuda, Dai Nakamura, Yasuhiko Matsunaga
  • Patent number: 8095819
    Abstract: A failure cause analysis system for estimating a cause of a failure in a communication network from recorded contents of internal processing of a communication apparatus includes: feature extraction means for extracting a statistical feature of the recorded contents at a time of occurrence of a failure; and failure cause estimation means for estimating a failure cause based on similarity between a statistical feature of the recorded contents that is acquired at a time of occurrence of a past failure with a known failure cause and the statistical feature of the recorded contents that is acquired at the time of occurrence of the failure.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: January 10, 2012
    Assignee: NEC Corporation
    Inventors: Yoshinori Watanabe, Yasuhiko Matsunaga
  • Patent number: 8084324
    Abstract: A nonvolatile semiconductor memory includes a memory cell transistor including a first floating gate electrode layer formed on a first tunneling insulating film, a first inter-gate insulating film, a first and a second control gate electrode layer, and a first metallic silicide film; a high voltage transistor including a high voltage gate electrode layer formed on the high voltage gate insulating film, a second inter-gate insulating film having an aperture, a third and a fourth control gate electrode layer, and a second metallic silicide film; a low voltage transistor including a second floating gate electrode layer formed on the second tunneling insulating film, a third inter-gate insulating film having an aperture, a fifth and a sixth control gate electrode layer, and a third metallic silicide film; and a liner insulating film directly disposed on a first source and drain region of the memory cell transistor, a second source and drain region of the low voltage transistor, and a third source and drain region
    Type: Grant
    Filed: March 9, 2010
    Date of Patent: December 27, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kikuko Sugimae, Masayuki Ichige, Fumitaka Arai, Yasuhiko Matsunaga, Atsuhiro Sato
  • Patent number: 8065568
    Abstract: The system for detecting a failure on a communication network according to an objective basis by analyzing an alarm log output by a management server of the communication network and evaluating a degree of abnormality of the communication network tracing back to a more significant factor causing the alarm, calculates an occurrence intensity of the more significant factor 500 causing an alarm based on the recording contents of the alarm, and detects a failure derived from the more significant factor of the communication network based on the calculated intensity of occurrence of said more significant factor 500.
    Type: Grant
    Filed: July 11, 2006
    Date of Patent: November 22, 2011
    Assignee: NEC Corporation
    Inventors: Yoshinori Watanabe, Yasuhiko Matsunaga
  • Publication number: 20110263244
    Abstract: A mobile terminal includes a measuring unit that measures at least the moving speed of the self terminal and communication quality of wireless communication, and a communication unit that transmits terminal information including moving speed information and communication quality information. A quality monitoring apparatus (90) includes a terminal information collection unit (901) that collects the terminal information from at least one mobile terminal, and a terminal information classification unit (903) and a quality analyzing unit (904) that monitor communication quality in a predetermined target area for each moving speed range of the mobile terminal based on the collected terminal information.
    Type: Application
    Filed: August 25, 2009
    Publication date: October 27, 2011
    Inventors: Kosei Kobayashi, Yasuhiko Matsunaga