Patents by Inventor Kazuo Kawabata

Kazuo Kawabata 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: 7912487
    Abstract: A mobile communication system in which, when transmission is performed from a base station to a terminal device, a modulation scheme is designated, from among at least two modulation schemes with different modulation levels, on the basis of reception quality at the terminal to perform transmission from the base station. The system includes a base station transmitting at a first transmission power using a frequency designed for, in a channel allocation scheme of the system, not causing interference with an adjacent base station and using a first modulation scheme, and a second channel transmitting at a second transmission power lower than the first transmission power, and when the base station uses the second channel, a second modulation scheme having a lower modulation level than the first modulation scheme is designated, and communication is performed.
    Type: Grant
    Filed: April 4, 2007
    Date of Patent: March 22, 2011
    Assignee: Fujitsu Limited
    Inventors: Yoshiharu Tajima, Kazuo Kawabata, Yoshiaki Ohta, Kazuhisa Obuchi, Hideto Furukawa, Yoshihiro Kawasaki
  • Publication number: 20100303000
    Abstract: A wireless relay device that transmits a reception signal from a transmission device to a reception device includes a determination section configured to determine whether or not the reception signal is a retransmission signal retransmitted from the transmission device, and an amplification section configured to amplify the reception signal when the determination section determines that the reception signal is the retransmission signal, and not to amplify the reception signal when the determination section determines that the reception signal is not the retransmission signal.
    Type: Application
    Filed: May 27, 2010
    Publication date: December 2, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Kotaro Shiizaki, Masafumi Tsutsui, Kazuo Kawabata
  • Publication number: 20100284362
    Abstract: The present method adds uplink data to a transmission request sent to the base station from the mobile station for obtaining permission for data transmission, or to a channel establishment request sent from the mobile station to the base station for establishing a channel in order to send the transmission request therethrough. This makes it possible to suppress delay caused by negotiation prior to actual uplink data transmission as much as possible, thereby realizing efficient uplink data transmission, that is, improved throughput of uplink communication.
    Type: Application
    Filed: June 21, 2010
    Publication date: November 11, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Yoshiharu TAJIMA, Hideto FURUKAWA, Kazuo KAWABATA, Yoshihiro KAWASAKI, Kazuhisa OBUCHI
  • Publication number: 20100248659
    Abstract: A wireless communication device includes a directional antenna that transmits radio signals, and an antenna control unit that measures, in a plurality of directions, spatial lengths from the wireless communication device to an object nearest the wireless communication device, and directs a directional antenna beam radiation direction toward a direction having the longest of the measured spatial lengths, when transmitting the radio signals.
    Type: Application
    Filed: March 22, 2010
    Publication date: September 30, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Kazuo Kawabata
  • Publication number: 20100232394
    Abstract: The present invention is a handover control method in a mobile communication system that performs handover control by switching base stations that communicate with a mobile terminal as the mobile terminal moves. In this handover control method, a mobile control device selects one or more handover base station candidates based on the communication state, and based on the communication capabilities of the handover base station candidates, decides a transmission rate for multicasting communication data, and transmits communication data to each of the handover base station candidates at the decided transmission rate, and a handover base station candidate that is decided as a handover base station sends the saved multicast communication data to the mobile terminal.
    Type: Application
    Filed: May 26, 2010
    Publication date: September 16, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Yoshiaki Ohta, Yoshiharu Tajima, Kazuo Kawabata
  • Publication number: 20100220681
    Abstract: A method for transmitting a control channel information to perform an adaptive coding and modulation comprising performing error correction coding at a predetermined coding rate for the control channel information; modulating according to a predetermined modulation scheme and transmitting the error correction coded control channel information; and further, prior to the modulation, performing code decimation or code repetition of the error correction coded signal, according to whether or not Multi Input Multi Output is applied.
    Type: Application
    Filed: May 10, 2010
    Publication date: September 2, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Kazuhisa OBUCHI, Hideto FURUKAWA, Kazuo KAWABATA, Yoshiharu TAJIMA, Yoshihiro KAWASAKI
  • Publication number: 20100190505
    Abstract: According to priorities determined on the basis of a number of pieces of battery information which concern batteries of a number of communication terminals and each of which is received from the communication terminals, data communication with communication terminals are controlled. The priorities are varied, irrespective of a variation in the pieces of battery information, according to a rule predetermined.
    Type: Application
    Filed: June 4, 2009
    Publication date: July 29, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Kotaro SHIIZAKI, Takao NAKAGAWA, Kazuo KAWABATA, Hiroyuki SEKI
  • Publication number: 20100142431
    Abstract: A technique for improving the efficiency of downloading transmission data is disclosed. An information downloading apparatus downloads differing sets of information to predetermined groups to which a mobile terminal may belong. This apparatus includes a channel selecting unit for selecting from plural information channels an information channel for transmitting transmission data and a transmitting unit for transmitting transmission data using the selected information channel. The channel selecting unit selects an information channel so that sets of transmission data with differing destination addresses may be transmitted through differing information channels. The transmitting unit transmits to each group, through a control channel, information pertaining to whether a set of transmission data exists, the information channel to be used if the set of transmission data exists, and the data length of the set of transmission data. The control channel includes time slots that are associated with the groups.
    Type: Application
    Filed: February 9, 2010
    Publication date: June 10, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Kazuo KAWABATA, Yoshiharu Tajima
  • Patent number: 7672276
    Abstract: Disclosed is a handover method in radio communication. A base station apparatus monitors the receiving state of a terminal, detects, based upon the receiving state, whether the terminal is one in which there is a possibility that loss of a call or a decline in quality will occur or one in which loss of a call or a decline in quality has occurred, and hands over the terminal to another base station apparatus having a carrier frequency different from that of the present base station apparatus.
    Type: Grant
    Filed: October 11, 2005
    Date of Patent: March 2, 2010
    Assignee: Fujitsu Limited
    Inventors: Takayoshi Ode, Kazuo Kawabata
  • Publication number: 20100046654
    Abstract: A communications system for communications by a multicarrier transmission mode between a plurality of communications apparatuses, wherein an overall frequency band assigned to the communications system is divided into a plurality of frequency bands each having a constant bandwidth and a specific band. The divided bands are used to transmit used frequency band information thereby indicating the assignment of the remaining bands used between said communications apparatuses. The specific band is defined as a main band for transmitting control channel information including used frequency band information and data channel information. The main band may be added with an extension band for transmitting further data channel information. The main band and extension band can be changed in the frequency band used along with time or can be changed in the number thereof. Both the main band and the extension bands are preferably used for multiplexing by some of communications apparatuses.
    Type: Application
    Filed: October 28, 2009
    Publication date: February 25, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Takayoshi Ode, Yoshihiro Kawasaki, Kazuo Kawabata
  • Publication number: 20100040161
    Abstract: In a wireless telecommunication system for transmitting a plurality of streams from a base transmission station comprising a plurality of antennas to a mobile station comprising a plurality of antennas, the base transmission station respectively transmits, by way of a plurality of the antennas, each stream obtained by dividing data to be transmitted. The mobile station respectively receives each stream by utilizing the plurality of antennas. A measurement unit respectively measures a reception quality or received power from each antenna relating to a stream. A changeover unit carries out a handover for each stream according to a measurement result by the measurement unit.
    Type: Application
    Filed: August 20, 2009
    Publication date: February 18, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Takayoshi ODE, Kazuo KAWABATA
  • Publication number: 20100039979
    Abstract: Controlling broadcast and multicast service communication including transmitting request signaling information for requesting broadcast and multicast service from a mobile station to a base station using preamble codes of specified random access channel (RACH) signals, and discriminating the preamble codes of the specified RACH signals from among preamble codes of RACH signals which have been received.
    Type: Application
    Filed: August 12, 2009
    Publication date: February 18, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Ryo TAKASE, Kazuo Kawabata
  • Publication number: 20100029333
    Abstract: A base transceiver station performing communications with user equipment, includes a receiving unit to receive an uplink transmission signal containing a propagation path fluctuation value between a self-device and the user equipment from the user equipment; and a communication permitting unit to control a period of time during which a permission of communications is given to the user equipment based on the propagation path fluctuation value.
    Type: Application
    Filed: October 12, 2009
    Publication date: February 4, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Kotaro SHIIZAKI, Ryusuke KIRYU, Kazuo KAWABATA
  • Publication number: 20100009693
    Abstract: In a base station, a received signal strength calculation unit calculates the received signal strength of data sent by wireless terminals. A scheduler re-allocates the wireless resource next to a wireless terminal that will cause the smallest change from the received signal strength of the currently allocated wireless terminal. The base station can receive data sent from the wireless terminals in such a manner that the received signal strength varies gradually, and degradation in quality of reception can be suppressed.
    Type: Application
    Filed: September 16, 2009
    Publication date: January 14, 2010
    Inventors: Kazuo KAWABATA, Ryusuke Kiryu
  • Publication number: 20090318156
    Abstract: Disclosed is a handover method in radio communication. A base station apparatus monitors the receiving state of a terminal, detects, based upon the receiving state, whether the terminal is one in which there is a possibility that loss of a call or a decline in quality will occur or one in which loss of a call or a decline in quality has occurred, and hands over the terminal to another base station apparatus having a carrier frequency different from that of the present base station apparatus.
    Type: Application
    Filed: August 31, 2009
    Publication date: December 24, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Takayoshi Ode, Kazuo Kawabata
  • Patent number: 7636583
    Abstract: In a wireless telecommunication system for transmitting a plurality of streams from a base transmission station comprising a plurality of antennas to a mobile station comprising a plurality of antennas, the base transmission station respectively transmits, by way of a plurality of the antennas, each stream obtained by dividing data to be transmitted. The mobile station respectively receives each stream by utilizing the plurality of antennas. A measurement unit respectively measures a reception quality or received power from each antenna relating to a stream. A change over unit carries out a handover for each stream according to a measurement result by the measurement unit.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: December 22, 2009
    Assignee: Fujitsu Limited
    Inventors: Takayoshi Ode, Kazuo Kawabata
  • Publication number: 20090311967
    Abstract: The ratio of the number of connection sequences started upon reception of a connection request signal transmitted from the mobile terminals to the number of completed connection sequences is monitored, and on the basis of the monitoring result, the presence or the absence of a congestion state in the communications network is evaluated.
    Type: Application
    Filed: June 5, 2009
    Publication date: December 17, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Ryo TAKASE, Kazuo KAWABATA
  • Publication number: 20090296667
    Abstract: A scheduling method for transmitting an uplink signal from a mobile station to a base station comprises transmitting the uplink signal in a first scheduling mode in which the mobile station can transmit the uplink data without permission of the base station if an uplink communication state between the base station and the mobile station is higher than or equal to a predetermined quality; and transmitting the uplink signal in a second scheduling mode in which the permission is necessary for the mobile station transmitting the uplink data if the uplink communication state is lower than the predetermined quality.
    Type: Application
    Filed: August 5, 2009
    Publication date: December 3, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Yoshiharu TAJIMA, Hideto Furukawa, Kazuo Kawabata, Yoshihiro Kawasaki, Kazuhisa Obuchi
  • Publication number: 20090238134
    Abstract: A wireless communication apparatus that transmits a wireless signal, the wireless communication apparatus including a dividing unit that divides data transmitted in a data area of a frame format of the wireless signal into a plurality of segments. The wireless communication apparatus includes an encoding unit that encodes the data segmented by the dividing unit segment by segment.
    Type: Application
    Filed: March 17, 2009
    Publication date: September 24, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Kotaro Shiizaki, Kazuo Kawabata, Hiroyuki Seki
  • Publication number: 20090238149
    Abstract: A first wireless base station providing a first wireless zone encodes a first signal to be transmitted to the first wireless zone at a first coding rate, and transmits the signal at a first transmitting power to the first wireless zone. A second wireless base station belonging to the first wireless zone and providing a second radio zone encodes a second signal common with the first signal at a second coding rate, and transmits the signal at a second transmitting power to the second wireless zone.
    Type: Application
    Filed: November 17, 2008
    Publication date: September 24, 2009
    Applicant: FUJITSU LIMITED
    Inventor: Kazuo KAWABATA