Patents by Inventor Yutaka Ohto

Yutaka Ohto 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: 7715348
    Abstract: The object of the invention is to prevent reduction of the system capacity caused by the use of a channelization code belonging to the secondary scrambling code. Instead of trying to select a channelization code belonging to each of the primary and secondary scrambling codes for one cell in a conventional manner, selection of a channelization code belonging to the primary scrambling code is tried sequentially for a plurality of cells (S02, S04). If the selection of the code has been failed, it is determined whether selection is tried again under a different condition (S06). Then, when trying again, selection of a channelization code belonging to the secondary scrambling code is tried sequentially for the plurality of cells (S07, S09).
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: May 11, 2010
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masafumi Masuda, Kazunori Obata, Yutaka Ohto
  • Patent number: 7092711
    Abstract: There is provided a neighbor cell notifying apparatus capable of implementing more efficient notification to a mobile station within a range that can be notified of and monitored, when the mobile station in communication using a plurality of cells is notified of neighbor cell information. This neighbor cell notifying apparatus includes a cell information extracting part for extracting neighbor cell information items for specifying respective neighbor cells corresponding to each of the cells; a cell rank determining part for, based on the neighbor cell information items extracted, determining ranks of neighbor cell information items that the mobile station is to be notified of, in favor of neighbor cell information items about neighbor cells common to the cells; and a cell information notifying part for notifying the mobile station of a predetermined number of neighbor cell information items among the neighbor cell information items on the basis of the ranks determined.
    Type: Grant
    Filed: December 4, 2003
    Date of Patent: August 15, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masafumi Masuda, Kota Fujimura, Yutaka Ohto
  • Patent number: 7088960
    Abstract: Disclosed is a mobile communication system whereby, to reduce the connection time, a mobile station closely located to a base wireless station is permitted to continue to use a common channel for exchanging signals, and to suppress an increase in interference, an individual channel is set for a mobile station located near the edge of a cell, and to obtain a stabilized communication quality and to prevent an increase in the connection time, the probability that the transmission power will reach an upper limit is reduced. When communication between a mobile station and a wireless base station is started, the wireless base station measures the transmission power and the communication quality in the communication with the mobile station and the utilization ratio for a common channel, and compares the obtained values with predetermined threshold values. When the obtained values are lower than the threshold values, the wireless base station continues to use the common channel for signal transmission/reception.
    Type: Grant
    Filed: June 23, 2003
    Date of Patent: August 8, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yasuhiro Kato, Takehiro Nakamura, Seizo Onoe, Akihiro Maebara, Yutaka Ohto, Shinji Ueda
  • Publication number: 20040213186
    Abstract: The object of the invention is to prevent reduction of the system capacity caused by the use of a channelization code belonging to the secondary scrambling code. Instead of trying to select a channelization code belonging to each of the primary and secondary scrambling codes for one cell in a conventional manner, selection of a channelization code belonging to the primary scrambling code is tried sequentially for a plurality of cells (S02, S04). If the selection of the code has been failed, it is determined whether selection is tried again under a different condition (S06). Then, when trying again, selection of a channelization code belonging to the secondary scrambling code is tried sequentially for the plurality of cells (S07, S09).
    Type: Application
    Filed: January 16, 2004
    Publication date: October 28, 2004
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masafumi Masuda, Kazunori Obata, Yutaka Ohto
  • Publication number: 20040166858
    Abstract: There is provided a neighbor cell notifying apparatus capable of implementing more efficient notification to a mobile station within a range that can be notified of and monitored, when the mobile station in communication using a plurality of cells is notified of neighbor cell information. This neighbor cell notifying apparatus includes a cell information extracting part for extracting neighbor cell information items for specifying respective neighbor cells corresponding to each of the cells; a cell rank determining part for, based on the neighbor cell information items extracted, determining ranks of neighbor cell information items that the mobile station is to be notified of, in favor of neighbor cell information items about neighbor cells common to the cells; and a cell information notifying part for notifying the mobile station of a predetermined number of neighbor cell information items among the neighbor cell information items on the basis of the ranks determined.
    Type: Application
    Filed: December 4, 2003
    Publication date: August 26, 2004
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masafumi Masuda, Kota Fujimura, Yutaka Ohto
  • Publication number: 20040005898
    Abstract: Disclosed is a mobile communication system whereby, to reduce the connection time, a mobile station closely located to a base wireless station is permitted to continue to use a common channel for exchanging signals, and to suppress an increase in interference, an individual channel is set for a mobile station located near the edge of a cell, and to obtain a stabilized communication quality and to prevent an increase in the connection time, the probability that the transmission power will reach an upper limit is reduced. When communication between a mobile station and a wireless base station is started, the wireless base station measures the transmission power and the communication quality in the communication with the mobile station and the utilization ratio for a common channel, and compares the obtained values with predetermined threshold values. When the obtained values are lower than the threshold values, the wireless base station continues to use the common channel for signal transmission/reception.
    Type: Application
    Filed: June 23, 2003
    Publication date: January 8, 2004
    Applicant: NTT DoCoMo, Inc.
    Inventors: Yasuhiro Kato, Takehiro Nakamura, Seizo Onoe, Akihiro Maebara, Yutaka Ohto, Shinji Ueda
  • Patent number: 5745492
    Abstract: A speech freeze-out method in a communication system for transmitting speech information, which is sent from public telephone terminals (1) to a control center (5) through voice channels, from the control center (5) to a base station (8) through time division multiplexing radio frequency channels (6), and from the base station (8) to mobile stations (17) through transponders (13). The freeze-out processing is carried out when the control center (5) feeds the speech information to the time division multiplexing radio frequency channels (6) so that the number of transmission channels from the base station (8) to the transponders (13) is limited within an upper limit value.
    Type: Grant
    Filed: January 31, 1996
    Date of Patent: April 28, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Yoshinobu Nakamura, Yutaka Ohto, Takashi Ueda, Tomoyuki Ohya