Patents by Inventor Masashige Shirakabe

Masashige Shirakabe 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: 9241306
    Abstract: A radio communication system includes multiple base stations including a first base station and a second base station, and a mobile station. A candidate base station selector selects multiple candidate base stations that are candidates for a radio access point for the mobile station on the basis of the reception powers reported by the mobile station. When the mobile station actually executes wireless communication with the base station, an access-point base station determiner determines, as an access-point base station that is the actual radio access point for the mobile station, a base station corresponding to a best reception quality among reception qualities measured in the protected resource and reception quality measured in the non-protected resource.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: January 19, 2016
    Assignee: NTT DOCOMO, INC.
    Inventors: Masashige Shirakabe, Akihito Morimoto, Nobuhiko Miki, Satoshi Nagata
  • Patent number: 9185710
    Abstract: A high-power radio base station includes a resource setter configured to determine a ratio of the number of second resources at which the radio communicator should stop radio transmission to the sum of the number of the second resources and the number of first resources at which the radio communicator should execute radio transmission. The resource setter determines the ratio on the basis of a first number and a second number, the first number being the number of mobile terminals that are assumed to be connected with the radio base station, rather than the low-power radio base station, when cell range expansion (CRE) is not applied, but are connected with the low-power radio base station by virtue of application of cell range expansion, the second number being the number of mobile terminals connected with the radio base station when cell range expansion is applied.
    Type: Grant
    Filed: March 26, 2013
    Date of Patent: November 10, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Masashige Shirakabe, Nobuhiko Miki, Yukihiko Okumura
  • Publication number: 20150119053
    Abstract: A high-power radio base station includes a resource setter configured to determine a ratio of the number of second resources at which the radio communicator should stop radio transmission to the sum of the number of the second resources and the number of first resources at which the radio communicator should execute radio transmission. The resource setter determines the ratio on the basis of a first number and a second number, the first number being the number of mobile terminals that are assumed to be connected with the radio base station, rather than the low-power radio base station, when cell range expansion (CRE) is not applied, but are connected with the low-power radio base station by virtue of application of cell range expansion, the second number being the number of mobile terminals connected with the radio base station when cell range expansion is applied.
    Type: Application
    Filed: March 26, 2013
    Publication date: April 30, 2015
    Applicant: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Masashige Shirakabe, Nobuhiko Miki, Yukihiko Okumura
  • Patent number: 8958800
    Abstract: A radio communication system includes a first radio base station, second radio base stations, and mobile stations. Each of the mobile stations measures a first reception characteristic value and a second reception characteristic value for respective radio waves. The first radio base station determines the radio base station to which each of the mobile stations should connect, according to the first reception characteristic value, and classifies the mobile stations into a first mobile-station group and a second mobile-station group according to the second characteristic values.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: February 17, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Nobuhiko Miki, Masashige Shirakabe
  • Patent number: 8868079
    Abstract: A radio communication system includes a first radio base station that forms a first cell; a plurality of second radio base stations each of which forms a second cell; and a mobile station provided with a radio communication unit that connects, by radio, to each radio base station. The first radio base station specifies a correction value according to the number of the second cells formed in the first cell of the first radio base station and signals the correction value to the mobile station. The mobile station corrects a characteristic value indicating the reception characteristic of radio waves from the second radio base station by using the correction value. Either the first radio base station or the mobile station selects the destination of the mobile station according to the characteristic value of the first radio base station and the corrected characteristic value of the second radio base station.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: October 21, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Akihito Morimoto, Nobuhiko Miki, Masashige Shirakabe
  • Publication number: 20140293878
    Abstract: A radio communication system includes multiple base stations including a first base station and a second base station, and a mobile station. A candidate base station selector selects multiple candidate base stations that are candidates for a radio access point for the mobile station on the basis of the reception powers reported by the mobile station. When the mobile station actually executes wireless communication with the base station, an access-point base station determiner determines, as an access-point base station that is the actual radio access point for the mobile station, a base station corresponding to a best reception quality among reception qualities measured in the protected resource and reception quality measured in the non-protected resource.
    Type: Application
    Filed: November 15, 2012
    Publication date: October 2, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Masashige Shirakabe, Akihito Morimoto, Nobuhiko Miki, Satoshi Nagata
  • Publication number: 20140024379
    Abstract: A radio communication system includes a first radio base station, second radio base stations, and mobile stations. Each of the mobile stations measures a first reception characteristic value and a second reception characteristic value for respective radio waves. The first radio base station determines the radio base station to which each of the mobile stations should connect, according to the first reception characteristic value, and classifies the mobile stations into a first mobile-station group and a second mobile-station group according to the second characteristic values.
    Type: Application
    Filed: July 18, 2012
    Publication date: January 23, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Nobuhiko Miki, Masashige Shirakabe
  • Publication number: 20140003275
    Abstract: In a radio communication system provided with first radio base stations, second radio base stations, and a mobile station, the first radio base stations execute transmission of radio signals to the mobile station, located in first cells, in a first period, and stop the transmission of the radio signals to the mobile station in a second period; and the second radio base stations execute transmission of radio signals to the mobile station, located in second cells, in both the first period and the second period. In the first period, first radio base stations and second radio base stations included in a coordinated-transmission base station set are capable of coordinating with each other to send radio signals, whereas, in the second period, the second radio base stations included in the coordinated-transmission base station set are capable of coordinating with each other to send radio signals.
    Type: Application
    Filed: July 18, 2012
    Publication date: January 2, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Nobuhiko Miki, Masashige Shirakabe
  • Publication number: 20130329596
    Abstract: A radio communication system includes a first radio base station that forms a first cell, second radio base stations that form second cells, and mobile stations that execute radio communication with radio base stations.
    Type: Application
    Filed: July 18, 2012
    Publication date: December 12, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Masashige Shirakabe, Akihito Morimoto, Nobuhiko Miki
  • Publication number: 20130252612
    Abstract: A radio communication system includes a first radio base station that forms a first cell; a plurality of second radio base stations each of which forms a second cell; and a mobile station provided with a radio communication unit that connects, by radio, to each radio base station. The first radio base station specifies a correction value according to the number of the second cells formed in the first cell of the first radio base station and signals the correction value to the mobile station. The mobile station corrects a characteristic value indicating the reception characteristic of radio waves from the second radio base station by using the correction value. Either the first radio base station or the mobile station selects the destination of the mobile station according to the characteristic value of the first radio base station and the corrected characteristic value of the second radio base station.
    Type: Application
    Filed: July 18, 2012
    Publication date: September 26, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Nobuhiko Miki, Masashige Shirakabe
  • Patent number: 8379577
    Abstract: A wireless resource assigning apparatus for assigning wireless resources to transmission data of a plurality of users is disclosed. The wireless resource assigning apparatus includes a scheduling part configured to start scheduling for all users from a first wireless resource among a plurality of wireless resources prioritized according to a predetermined criterion, and repeat scheduling up to the last wireless resource for users except for users to whom any wireless resource has been assigned.
    Type: Grant
    Filed: February 24, 2006
    Date of Patent: February 19, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masashige Shirakabe, Naoto Matoba, Takatoshi Sugiyama, Hitoshi Yoshino, Tatsuro Masamura
  • Patent number: 8135356
    Abstract: To provide a radio communication control apparatus and a radio communication control method capable of controlling simultaneous transmission and reception so as not to degrade system throughput. A simultaneous transmission and reception controller 106 determines whether the simultaneous transmission and reception using the same frequency are possible, based on radio spectrum environment information of an opposite party of communication and radio spectrum environment information of a self-apparatus. When the simultaneous transmission and reception using the same frequency are determined to be possible, a control signal transmission section 109 transmits instruction information, indicating that the simultaneous transmission and reception are possible, and a transmission parameter thereof, to the above communication terminal.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: March 13, 2012
    Assignee: NTT Docomo, Inc.
    Inventors: Masashige Shirakabe, Takahiro Asai, Naoto Matoba, Hitoshi Yoshino
  • Publication number: 20110292916
    Abstract: Provided are a radio packet type determining section that determines at least whether a radio packet is a first transmission packet that is allocated persistently at predetermined time intervals or a retransmission packet among radio packets transmitted to a radio communication terminal, a first transmission interval control section that controls a transmission interval of each first transmission packet so as to disperse the first transmission packet and a retransmission packet of a radio packet index different from that of the first transmission packet, a retransmission interval control section that controls a transmission interval of each retransmission packet, and a radio resource allocation section that performs allocation of radio resources based on the transmission interval of each first transmission packet and the transmission interval of each retransmission packet.
    Type: Application
    Filed: May 25, 2011
    Publication date: December 1, 2011
    Applicant: NTT DOCOMO, INC.
    Inventors: Masashige Shirakabe, Kei Kikuiri, Akihito Hanaki, Yoshiaki Ofuji
  • Publication number: 20110255439
    Abstract: To provide a radio communication control apparatus and a radio communication control method capable of controlling simultaneous transmission and reception so as not to degrade system throughput. A simultaneous transmission and reception controller 106 determines whether the simultaneous transmission and reception using the same frequency are possible, based on radio spectrum environment information of an opposite party of communication and radio spectrum environment information of a self-apparatus. When the simultaneous transmission and reception using the same frequency are determined to be possible, a control signal transmission section 109 transmits instruction information, indicating that the simultaneous transmission and reception are possible, and a transmission parameter thereof, to the above communication terminal.
    Type: Application
    Filed: June 28, 2011
    Publication date: October 20, 2011
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masashige Shirakabe, Takahiro Asai, Naoto Matoba, Hitoshi Yoshino
  • Patent number: 8041311
    Abstract: To provide a radio communication control apparatus and a radio communication control method capable of controlling simultaneous transmission and reception so as not to degrade system throughput. A simultaneous transmission and reception controller 106 determines whether the simultaneous transmission and reception using the same frequency are possible, based on radio spectrum environment information of an opposite party of communication and radio spectrum environment information of a self-apparatus. When the simultaneous transmission and reception using the same frequency are determined to be possible, a control signal transmission section 109 transmits instruction information, indicating that the simultaneous transmission and reception are possible, and a transmission parameter thereof, to the above communication terminal.
    Type: Grant
    Filed: September 7, 2007
    Date of Patent: October 18, 2011
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masashige Shirakabe, Takahiro Asai, Naoto Matoba, Hitoshi Yoshino
  • Publication number: 20110134892
    Abstract: A radio base station of the present invention is provided with an index setting unit configured to set an index to a radio resource in a frequency domain, a resource allocation class determining unit is configured to determine a resource allocation class of a radio communication terminal from among resource allocation classes which are classified according to radio resource allocation patterns fixedly allocated at a fixed time interval T0, based on user information of the radio communication terminal, and a resource allocation unit configured to allocate a vacant radio resource within the fixed time interval T0 to the radio communication terminal in order starting with a radio resource having an index value predetermined for the resource allocation class.
    Type: Application
    Filed: December 3, 2010
    Publication date: June 9, 2011
    Applicant: NTT DOCOMO, INC.
    Inventors: Masashige Shirakabe, Takahiro Asai, Akihito Hanaki, Yoshiaki Ofuji
  • Patent number: 7865192
    Abstract: A radio frequency selection device in a radio communication system in which a radio communication channel is established between a mobile station and a base station by allocating a radio communication frequency band different from other radio communication system frequency bands is disclosed. The radio frequency selection device comprises: a frequency band determining unit that determines a radio control channel frequency band for transmitting control information, among frequency bands allocated to the radio communication system, based on the allocated radio communication channel frequency band; and a radio control channel establishing unit that establishes a radio control channel among the determined radio control channel frequency bands.
    Type: Grant
    Filed: June 13, 2005
    Date of Patent: January 4, 2011
    Assignee: NTT DoCoMo, Inc.
    Inventors: Satoru Fukumoto, Masashige Shirakabe, Hitoshi Yoshino
  • Patent number: 7689186
    Abstract: A frequency band allocation device is disclosed. The frequency band allocation device comprises a frequency band selection unit for selecting usable frequency bands from a dedicated frequency band, a registered frequency band and an unlicensed frequency band; and a frequency band allocation unit for allocating a frequency band out of the selected usable frequency bands to a user, so as to satisfy user required QoS and maximize system frequency utilization factor.
    Type: Grant
    Filed: September 22, 2005
    Date of Patent: March 30, 2010
    Assignee: NTT DoCoMo, Inc.
    Inventors: Naoto Matoba, Masashige Shirakabe, Takatoshi Sugiyama, Hitoshi Yoshino
  • Patent number: 7502341
    Abstract: A transmitter used in the multiband environment includes a frequency allocation unit (106) configured to select and allocate a frequency band that satisfies a user QoS from among multiple separate frequency bands currently available for the user, a parameter determination unit (111) configured to determine a transmission parameter required for signal transmission based on the allocated frequency band, and a multi-user scheduling control unit (110) configured to determine a transmission schedule for multiple users taking into account the frequency bands allocated to the multiple users.
    Type: Grant
    Filed: September 22, 2005
    Date of Patent: March 10, 2009
    Assignee: NTT DoCoMo, Inc.
    Inventors: Naoto Matoba, Masashige Shirakabe, Takatoshi Sugiyama, Hitoshi Yoshino
  • Patent number: 7415275
    Abstract: A frequency selection apparatus, a mobile communications system, and a multi-band resource management method are disclosed. The frequency selection apparatus includes an acquisition unit configured to collect environmental information about a mobile station for each frequency band according to system frequency bands that a mobile station can use, and a frequency selection unit configured to determine the frequency band to be used and the system to be connected to, based on the environmental information and information provided by the mobile station.
    Type: Grant
    Filed: May 27, 2005
    Date of Patent: August 19, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masashige Shirakabe, Satoru Fukumoto, Hitoshi Yoshino