Patents by Inventor Kiyohito Nagata

Kiyohito Nagata 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: 7082310
    Abstract: Among cellular radio communication systems, there are those in which a plurality of businesses, e.g. businesses A, B and C share a designated frequency band, and each business provides radio communication services using respectively allotted frequency bands. In this type of radio communication system, there are cases in which mobile stations belonging to different businesses use channels which have adjacent frequencies, in which case adjacent channel interference of a large interference level is produced. Therefore, in this radio communication system, of the frequency bands allotted to each business, the adjacent frequency bands which are adjacent to frequency bands allotted to other businesses are allotted to low power communications, while non-adjacent frequency bands which are not adjacent to frequency bands allotted to other businesses are allotted to high power communications.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: July 25, 2006
    Assignee: NTT Mobile Communications Networks, Inc.
    Inventors: Tomoaki Hirayama, Tadao Takami, Kiyohito Nagata
  • Publication number: 20040082335
    Abstract: Among cellular radio communication systems, there are those in which a plurality of businesses, e.g. businesses A, B and C share a designated frequency band, and each business provides radio communication services using respectively allotted frequency bands. In this type of radio communication system, there are cases in which mobile stations belonging to different businesses use channels which have adjacent frequencies, in which case adjacent channel interference of a large interference level is produced. Therefore, in this radio communication system, of the frequency bands allotted to each business, the adjacent frequency bands which are adjacent to frequency bands allotted to other businesses are allotted to low power communications, while non-adjacent frequency bands which are not adjacent to frequency bands allotted to other businesses are allotted to high power communications.
    Type: Application
    Filed: July 29, 2003
    Publication date: April 29, 2004
    Inventors: Tomoaki Hirayama, Tadao Takami, Kiyohito Nagata
  • Patent number: 6658257
    Abstract: Among cellular radio communication systems, there are those in which a plurality of businesses, e.g. businesses A, B and C share a designated frequency band, and each business provides radio communication services using respectively allotted frequency bands. In this type of radio communication system, there are cases in which mobile stations belonging to different businesses use channels which have adjacent frequencies, in which case adjacent channel interference of a large interference level is produced. Therefore, in this radio communication system, of the frequency bands allotted to each business, the adjacent frequency bands which are adjacent to frequency bands allotted to other businesses are allotted to low power communications, while non-adjacent frequency bands which are not adjacent to frequency bands allotted to other businesses are allotted to high power communications.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: December 2, 2003
    Assignee: NTT DoCoMo, Inc.
    Inventors: Tomoaki Hirayama, Tadao Takami, Kiyohito Nagata
  • Patent number: 6556552
    Abstract: In CDMA mobile communication systems, there are cases in which communications are interrupted with the local base station while the mobile station is searching for channels other than the communication channel. A method is offered of preventing loss of information due to interruptions in such a case. There are a first transmission step for transmitting signals from the mobile station to the base station at a transmission rate R1 and a transmission output level P1 (when the transmission output is p in FIG. 10C), a suspension step of suspending signal transmissions from the mobile station to the base station (when no transmission output power as shown in the same drawing), and a second transmission step of transmitting signals from the mobile station to the base station at a transmission rate R2 higher than the transmission rate R1 and a transmission output level P2 higher than the transmission output level P1 (when 2p in the same drawing).
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: April 29, 2003
    Assignee: NTT Communications Networks, Inc.
    Inventors: Hisashi Nakagomi, Tadao Takami, Akihiro Higashi, Kiyohito Nagata
  • Patent number: 5983097
    Abstract: A mobile communication scheme capable of notifying a communication regulation information efficiently by using radio interfaces from the macro-cell system to the micro-cell system, without requiring communications through a fixed communication network, so as to be able to regulate the service through the micro-cell system efficiently in coordination with the regulation of the service through the macro-cell system. In this mobile communication scheme, the communication regulation information is notified from the macro-cell system to the mobile station while the mobile station is located within the macro-cell system, and stored in a memory of the mobile station.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: November 9, 1999
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Kazuhiko Kakinuma, Masaaki Yoshimi, Tatsuaki Wakabayashi, Kiyohito Nagata
  • Patent number: 5826197
    Abstract: A mobile communication system having a high precision frequency base station device with a high precision frequency generator, and the other low precision frequency base station device with a low precision frequency generator which receives transmission waves from the high precision frequency base station device using a transmission frequency in a prescribed frequency precision, and carries out transmission and reception by controlling transmission and reception frequencies of own station in accordance with the frequency precision of the received transmission waves.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: October 20, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kiyohito Nagata, Teruya Fujii, Katsunori Hamada, Kazuhiko Kakinuma, Masaaki Yoshimi, Tatsuaki Wakabayashi
  • Patent number: 5732327
    Abstract: Each base station measures the field intensity of downlink rediowaves from other base stations, then analyzes the received rediowaves above a predetermined field intensity value and decides whether they are rediowaves used in the same mobile radio communication system. The base station creates peripheral base station information based on information about the rediowaves decided as being used in the same mobile radio communication system.
    Type: Grant
    Filed: December 19, 1995
    Date of Patent: March 24, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Masaaki Yoshimi, Kiyohito Nagata, Kazuhiko Kakinuma, Tatsuaki Wakabayashi
  • Patent number: 5603093
    Abstract: A mobile station measures the field intensity and bit error rate of a downlink radio wave from a base station at each measurement timing and reports the measured results to the base station. Upon receiving the measured results from each mobile station, the base station compares the measured results with a reference characteristic to determine if they are abnormal or not. The base station acquires the determined results of the measured results for a fixed period of time and statistically processes them to judge the state of interference.
    Type: Grant
    Filed: December 13, 1995
    Date of Patent: February 11, 1997
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Masaaki Yoshimi, Kiyohito Nagata, Kazuhiko Kakinuma, Tatsuaki Wakabayashi
  • Patent number: 5408684
    Abstract: In the selection of a control channel of a mobile station in a radio zone to which some control channels are assigned as communication channels, the receiving levels of the control channels are sequentially measured and control channel candidates are selected. A check is made to see if a control signal can correctly be received in each of the selected control channel candidates, and if not, the number of signal reception failures in that channel is incremented by 1 in a memory used by the mobile rotation. A channel in which the number of signal reception failures has reached a predetermined value M (an integer equal to or greater than 1) is excluded from the group of control channel candidates, and the other selected control channel candidates are similarly checked to determine whether or not the reception of the control signal is possible in each of them.
    Type: Grant
    Filed: September 1, 1993
    Date of Patent: April 18, 1995
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kazufumi Yunoki, Katsumi Kobayashi, Kiyohito Nagata