Patents by Inventor Tomonori Yamamoto

Tomonori Yamamoto 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: 8463272
    Abstract: An object of the invention is to provide a wireless communication system in which the load of each cell and interference between cells are taken into account. In a handover-candidate base station and a handover-source base station, parameters for interference-reducing scheduling and handover facilitating processing are adjusted based on the mutual load information. When the handover-candidate base station, to be used for load balancing, is a large-diameter cell, transmit power control and frequency scheduling are adjusted by taking account of the load state at a cell edge. When the handover-source base station has a small-diameter cell, the number of terminals to be handed over is adjusted by taking account of the load state of the handover-candidate base station. Thus, both of interference control and load balancing are achieved.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: June 11, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Tomonori Yamamoto, Satoshi Tamaki, Rintaro Katayama, Hirotake Ishii
  • Patent number: 8344583
    Abstract: Provided is an automotive alternator having structure for preventing entry and discharging of foreign matters irrespective of a posture of a brush unit, to thereby allow normalization of the brush unit. The brush unit of the automotive alternator includes a slip ring, a brush, a brush holder, and a slip ring cover coaxially spaced from the slip ring and having an inner peripheral surface surrounding substantially an entire periphery of the slip ring. The inner peripheral surface of the slip ring cover has a tapered surface increasing in diameter from a first end on the frame side toward a second end having a fully-open opening. The fully-open opening is sealed by a sealing member that forms a labyrinth seal with the second end.
    Type: Grant
    Filed: November 1, 2010
    Date of Patent: January 1, 2013
    Assignee: Mitsubishi Electric Corp.
    Inventor: Tomonori Yamamoto
  • Publication number: 20120281569
    Abstract: Timing division multiplexing is conducted between the cells to avoid intercell interference. Transmission timing in a time slot pattern has a given interval. A base station determines the transmission timing based on measured uplink interference power. For example, an uplink time slot pattern in which the measured uplink interference power is smaller is selected. A downlink time slot pattern is assigned so that a response to HARQ is returned at that timing. If traffic is busy, additional time slot pattern may be assigned. In determination of the traffic volume, for example, the queued buffer size, the number of connected terminals, or the number of connections to a higher-level device can be used. Assignment timing can be an initial setup time, or a fluctuation detection time of a channel which can be realized by collection of report information on a downlink communication quality, periodic monitor of uplink interference information.
    Type: Application
    Filed: May 2, 2012
    Publication date: November 8, 2012
    Applicant: HITACHI, LTD.
    Inventors: Tomonori YAMAMOTO, Rintaro KATAYAMA, Keisuke TAKEUCHI
  • Publication number: 20120120876
    Abstract: In a cellular radio communication system, a base station or a mobile station has a TA (Time Alignment)-range-out detection function, so that when a TA-range-out state that is unable to compensate with a guard interval is detected, the transmission condition of an uplink signal at the mobile station is changed by the mobile station autonomously or by the base station and the mobile station cooperatively.
    Type: Application
    Filed: January 24, 2012
    Publication date: May 17, 2012
    Inventors: Tomonori YAMAMOTO, Katsuhiko TSUNEHARA, Satoshi TAMAKI, May TAKADA, Mikio KUWAHARA
  • Patent number: 8111683
    Abstract: In a cellular radio communication system, a base station or a mobile station has a TA (Time Alignment)-range-out detection function, so that when a TA-range-out state that is unable to compensate with a guard interval is detected, the transmission condition of an uplink signal at the mobile station is changed by the mobile station autonomously or by the base station and the mobile station cooperatively.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: February 7, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Tomonori Yamamoto, Katsuhiko Tsunehara, Satoshi Tamaki, May Takada, Mikio Kuwahara
  • Publication number: 20120028630
    Abstract: A femtocell base station collects the terminal distribution within the cell and selects terminals to represent the cell-center and the cell-edge from among the terminals within the cell. The femtocell base station also calculates maximum transmit power for the respective the cell-center and cell-edge terminals allowable by the macrocell base station. The femtocell base station sets the respective transmit power of the cell-center and the cell-edge in a range that will not exceed the maximum transmit power, adjusts the transmit power control parameter to allow control by the terminal at the power value that was set, and notifies the terminal. Communication with high throughput can in this way be attained for terminals in cells within the femtocell base station during uplink communications to the femtocell base station, and interference applied to the terminals in the macrocell base station can be suppressed.
    Type: Application
    Filed: June 22, 2011
    Publication date: February 2, 2012
    Applicant: Hitachi, Ltd.
    Inventors: Tomonori YAMAMOTO, Rintaro Katayama, Hirotake Ishii
  • Publication number: 20110317742
    Abstract: A cellular radio communication system includes a first mobile terminal, a base station that performs radio communication with first mobile terminals, a second mobile terminal, and a second base station that performs radio communication with second mobile terminals. In the downlink communication, the base station selects a high data rate mode when the radio interference from the base station to the second mobile terminals that are located close to an edge of a communication area of the second base station is small. The base station selects an interference mitigation mode in the downlink communication when the radio interference from the base station to the second mobile terminals that are located close to the edge of the communication area of the second base station is large. Thus, inter-cell interference control can be performed in collaboration with base stations in the radio communication system without having communication interface between the base stations.
    Type: Application
    Filed: June 2, 2011
    Publication date: December 29, 2011
    Inventors: Takuji Kawahatsu, Rintaro Katayama, Satoshi Tamaki, Tomonori Yamamoto
  • Publication number: 20110310758
    Abstract: A method for assigning resources of a radio communication system that is aimed at relaxing interference between cells and that is applicable even in the case where femtocell base stations are installed within a macrocell base station area, and a radio base station apparatus. A transmit power limitation that limits an allocatable resource for each subband consisting of one or plural sub-carriers is decided, resource assignment is preformed on a mobile terminal on a subband-by-subband basis by a scheduler so that the transmit power limitation may be satisfied, and the transmit power limitation is altered based on an estimation result of an interference quantity from surrounding cells.
    Type: Application
    Filed: June 14, 2011
    Publication date: December 22, 2011
    Applicant: Hitachi, Ltd.
    Inventors: Satoshi Tamaki, Rintaro Katayama, Tomonori Yamamoto, Hirotake Ishii
  • Publication number: 20110291505
    Abstract: Provided is an automotive alternator having structure for preventing entry and discharging of foreign matters irrespective of a posture of a brush unit, to thereby allow normalization of the brush unit. The brush unit of the automotive alternator includes a slip ring, a brush, a brush holder, and a slip ring cover coaxially spaced from the slip ring and having an inner peripheral surface surrounding substantially an entire periphery of the slip ring. The inner peripheral surface of the slip ring cover has a tapered surface increasing in diameter from a first end on the frame side toward a second end having a fully-open opening. The fully-open opening is sealed by a sealing member that forms a labyrinth seal with the second end.
    Type: Application
    Filed: November 1, 2010
    Publication date: December 1, 2011
    Applicant: MITSUBISHI ELECTRIC CORP.
    Inventor: Tomonori YAMAMOTO
  • Publication number: 20110244866
    Abstract: An object of the invention is to provide a wireless communication system in which the load of each cell and interference between cells are taken into account. In a handover-candidate base station and a handover-source base station, parameters for interference-reducing scheduling and handover facilitating processing are adjusted based on the mutual load information. When the handover-candidate base station, to be used for load balancing, is a large-diameter cell, transmit power control and frequency scheduling are adjusted by taking account of the load state at a cell edge. When the handover-source base station has a small-diameter cell, the number of terminals to be handed over is adjusted by taking account of the load state of the handover-candidate base station. Thus, both of interference control and load balancing are achieved.
    Type: Application
    Filed: January 6, 2011
    Publication date: October 6, 2011
    Inventors: Tomonori YAMAMOTO, Satoshi Tamaki, Rintaro Katayama, Hirotake Ishii
  • Publication number: 20110212744
    Abstract: A communication device includes pilot signal sending part and transmit power control part and holds a criterion value indicating target channel quality for mobile stations within the area covered by the base station. It creates quality data from reports from one or plural mobile stations, stores the quality data, creates a first representative value indicating average channel quality for the mobile station(s) from the stored quality data, and changes the transmit power depending on the result of comparison between the first representative value and the criterion value. It creates a second representative value indicating distribution of low channel quality from the stored quality data and updates the criterion value depending on the result of comparison between the second representative value and the criterion value.
    Type: Application
    Filed: January 7, 2011
    Publication date: September 1, 2011
    Inventors: Rintaro KATAYAMA, Satoshi Tamaki, Tomonori Yamamoto, Hirotake Ishii, Shigenori Hayase
  • Publication number: 20110211560
    Abstract: Interference applied to neighbor cells during terminal handovers can be reduced in wireless communication systems containing base stations having different cell sizes. A serving cell makes handover judgment criteria easier based on pre-acquired cell size information on its own cell and cell size information of neighbor cells in order to facilitate terminal handovers from a base station with a large cell size to a base station with a small cell size. The serving cell finds evaluation function values based on the propagation state (e.g. reference signal received power) between the terminal and target cell, and the interference and load information exchanged between the base stations, and selects the terminal for handover by comparing the evaluation function value with the handover criteria value. The system selects a target cell having a good effect in lowering interference such as a cell with large reference signal received power acquired from a terminal, to serve as the handover destination.
    Type: Application
    Filed: February 11, 2011
    Publication date: September 1, 2011
    Inventors: Tomonori YAMAMOTO, Satoshi Tamaki, Rintaro Katayama, Hirotake Ishii
  • Publication number: 20110211519
    Abstract: In a time slot in which a first base station for performing a multicast transmission executes the multicast transmission, a second base station which does not perform the multicast transmission does not perform a unicast data transmission. The time slot in which the first base station performs the multicast transmission is notified to the second base station from a multicast control apparatus for performing scheduling of the multicast transmission to the first base station. Information to receive the multicast transmission is notified from the second base station to a terminal connected to the second base station.
    Type: Application
    Filed: January 28, 2011
    Publication date: September 1, 2011
    Inventors: Rintaro KATAYAMA, Satoshi Tamaki, Tomonori Yamamoto, Hirotake Ishii
  • Publication number: 20110201885
    Abstract: A surgical robot including an imaging system comprising at least one camera, a processor in communication with the imaging system, a manipulation system in communication with the processor, and a visual display in communication with the processor. The processor is operable to calculate a stiffness estimate for an area of an environment based on an environment model of tool-environment interaction data, create a composite image comprising a stiffness map of the stiffness estimate overlaid on an environment image from the at least one camera, and output the composite image on the visual display.
    Type: Application
    Filed: October 20, 2009
    Publication date: August 18, 2011
    Applicant: The Johns Hopkins University
    Inventors: Allison Mariko Okamura, Tomonori Yamamoto, Peter Balazs Vagvolgyi
  • Publication number: 20110064061
    Abstract: Conventionally, different HARQ processes 801 and 802 (subframes T1 and T2) transmit data packets B and D, respectively. One data packet corresponds to one process and is retransmitted as necessary one by one on a process basis, degrading the usage efficiency of frequency and time resources. To solve this problem, downlink data packets B and D, when needed to be retransmitted, are spatially multiplexed in the different HARQ processes 801 and 802. The data packets are simultaneously retransmitted to the same terminal as process 805 (subframe T3).
    Type: Application
    Filed: August 5, 2010
    Publication date: March 17, 2011
    Applicant: HITACHI, LTD.
    Inventors: Keisuke TAKEUCHI, Rintaro KATAYAMA, Tomonori YAMAMOTO, Koki UWANO
  • Publication number: 20100311430
    Abstract: In a radio-communication system, when wanting to perform high-accuracy scheduling in a base station, a large number of information items, such as channel quality information, desired precoding matrix information and so on, are fed back from a mobile station with a high degree of accuracy. The base station monitors the feedback information and, upon acquisition of it, transmits to the mobile station a certain kind of feedback information which is judged to contribute to scheduling accuracy improvement while preventing the other kinds of feedback information from being sent to the mobile station.
    Type: Application
    Filed: June 1, 2010
    Publication date: December 9, 2010
    Applicant: HITACHI, LTD.
    Inventors: Rintaro KATAYAMA, Satoshi TAMAKI, Tomonori YAMAMOTO, Hirotake ISHII
  • Publication number: 20100309866
    Abstract: In a system of the present invention, the amount of cell-edge band is limited. In addition, the upper limit of the amount of cell-edge band in each cell is set for limiting the amount of cell-edge band based on the upper limit. The number of cell-edge MSs is also limited. In addition, the upper limit of the number of cell-edge MSs in each cell is set for limiting the number of cell-edge MSs based on the upper limit.
    Type: Application
    Filed: June 2, 2010
    Publication date: December 9, 2010
    Applicant: HITACHI, LTD.
    Inventors: Rintaro KATAYAMA, Satoshi TAMAKI, Tomonori YAMAMOTO, Hirotake ISHII
  • Publication number: 20100309864
    Abstract: Resources are assigned in units of resource blocks each composed of one or more subcarriers, inter-cell interference adjustment control information is notified to each other among base stations, a transmit power limitation on each of the resource blocks in a cell is decided based on the inter-cell interference adjustment control information; and the decision of the transmit power limitation is changed sequentially beginning at a resource block having a transmit power limitation different from the transmit power limitation on an adjacent resource block.
    Type: Application
    Filed: May 27, 2010
    Publication date: December 9, 2010
    Applicant: HITACHI, LTD.
    Inventors: Satoshi TAMAKI, Rintaro KATAYAMA, Hirotake ISHII, Tomonori YAMAMOTO
  • Publication number: 20100238876
    Abstract: A method for radio resource control is carried out in a radio communications system including multiple base stations. In this method, a radio resource that can be used by the base stations is divided into multiple first radio resources on the frequency axis. Then one or more of the first radio resources are allocated to a second radio resource for initially transmitting a packet and the other first radio resources are allocated to a third radio resource for retransmitting the packet.
    Type: Application
    Filed: February 18, 2010
    Publication date: September 23, 2010
    Applicant: HITACHI, LTD.
    Inventors: Tomonori YAMAMOTO, Rintaro KATAYAMA, Keisuke TAKEUCHI, Koki UWANO
  • Publication number: 20100182972
    Abstract: In a conventional OFDMA/SCFDMA communication scheme, frequency resource assignment information is exchanged between BSs via a wired interface and used for control of inter-cell interference or the like. When a BS performs assignments of frequency resources, taking the status of a neighbor BS signaled via the wired interface into account, it might be impossible to follow a change in the status of the assignments of frequency resources at the neighbor BS due to a delay occurring in the wired interface. BS selects and assigns distributed frequency resources or continuous frequency resources, depending on the position of an MS in the cell and the transmit power of the BS.
    Type: Application
    Filed: January 19, 2010
    Publication date: July 22, 2010
    Applicant: HITACHI, LTD.
    Inventors: Rintaro KATAYAMA, Keisuke TAKEUCHI, Tomonori YAMAMOTO, Koki UWANO