Patents by Inventor Yoshiaki Ofuji

Yoshiaki Ofuji 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: 10020873
    Abstract: Even in the case of satellite communications to which LTE is applied, a difference between reception timings of uplink singles transmitted from a plurality of mobile stations UE located in the same cell is kept within GI specified in LTE. A mobile station UE#1 according to the present invention includes: an offset calculation unit 23 configured to calculate an offset ? from a transmission timing to be referenced, based on a distance Lx between the mobile station UE#1 and a satellite 1 used in satellite communications, and a distance Lref between the satellite 1 and a reference mobile station UE; and an RACH functional unit 24 configured to adjust a transmission timing of a random access preamble based on the calculated offset ?.
    Type: Grant
    Filed: July 18, 2014
    Date of Patent: July 10, 2018
    Assignee: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Yoshiaki Ofuji, Kohei Kiyoshima
  • Patent number: 9590777
    Abstract: A base station 100 includes a scheduling processing unit 109 configured to schedule each of multiple mobile stations to the PDCCH, and a UE-type judgment unit 107 configured to judge whether each of the mobile stations is an OLD UE supporting only CFI=1 to 3 or a NEW UE supporting CFI=1 to 4. The scheduling processing unit 109 schedules each of the multiple UEs to the PDCCH by use of any one of CFI=1 to 3 when UEs targeted to be scheduled to the PDCCH include an OLD UE.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: March 7, 2017
    Assignee: NTT DOCOMO, INC.
    Inventors: Naoto Ookubo, Yoshiaki Ofuji
  • Publication number: 20160381611
    Abstract: Some techniques for implementing proper RACH-less handover control are provided. One aspect of the present invention relates to a base station including a communication control unit configured to control radio communication with user equipment, a capable cell information storage unit configured to store capable cell information indicating a RACH-less handover capable cell and a RACH-less handover determination unit configured to determine whether the user equipment is RACH-less handover capable.
    Type: Application
    Filed: August 24, 2015
    Publication date: December 29, 2016
    Applicant: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Hideaki Takahashi, Wuri Andarmawanti Hapsari, Yoshiaki Ofuji
  • Publication number: 20160174246
    Abstract: Even in the case of satellite communications to which LTE is applied, high transmission rates are achieved with avoidance of the occurrence of a delay. A radio base station eNB according to the present invention includes a transmission unit 11 configured to transmit a scheduling signal for a downlink signal and the downlink signal to a mobile station UE. The transmission unit 11 is configured not to wait to receive acknowledgement information for the downlink signal, but to transmit a downlink signal having the same contents as the downlink signal to the mobile station UE in a predetermined number of sub-frames.
    Type: Application
    Filed: July 28, 2014
    Publication date: June 16, 2016
    Applicant: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Yoshiaki Ofuji, Kohei Kiyoshima
  • Publication number: 20160173188
    Abstract: Even in the case of satellite communications to which LTE is applied, a difference between reception timings of uplink singles transmitted from a plurality of mobile stations UE located in the same cell is kept within GI specified in LTE. A mobile station UE#1 according to the present invention includes: an offset calculation unit 23 configured to calculate an offset ? from a transmission timing to be referenced, based on a distance Lx between the mobile station UE#1 and a satellite 1 used in satellite communications, and a distance Lref between the satellite 1 and a reference mobile station UE; and an RACH functional unit 24 configured to adjust a transmission timing of a random access preamble based on the calculated offset ?.
    Type: Application
    Filed: July 18, 2014
    Publication date: June 16, 2016
    Applicant: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Yoshiaki Ofuji, Kohei Kiyoshima
  • Patent number: 9240926
    Abstract: A base station 100 maps the system information formed of multiple blocks (SIB) to predetermined regions of a downlink shared channel and transmits the mapped system information to the mobile station. The base station 100 includes: a system information transmission control unit 105 configured to divide each of the predetermined regions into a first half and a second half in a time direction; and a transmission data generation unit 111 configured to map the system information to at least one of the first half and the second half. The system information transmission control unit 105 switches positions of the first half and the second half in rotation every transmission timing of the predetermined regions on the shared channel.
    Type: Grant
    Filed: August 3, 2012
    Date of Patent: January 19, 2016
    Assignee: NTT DOCOMO, INC.
    Inventors: Yoshiaki Ofuji, Naoto Ookubo
  • Patent number: 8954085
    Abstract: A base station allocates a radio resource to a scheduling-target user based on a scheduling metric which is calculated for each of scheduling-target users and calculates the amount of available data for each user. When the radio resource is allocated to the scheduling-target user, the amount of data (Dassign) to be communicated using the allocated radio resource is subtracted from the amount of available data (Davailable) for the user. The amount of available data (Davailable) for each user within a cell is updated (min((Davailable+Dref), Dref)) to be less than or equal to a reference data amount in each control period (TAMBR). The scheduling-target user is selected based on the amount of available data for each user.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: February 10, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Naoto Okubo, Yoshiaki Ofuji, Hiroyuki Ishii, Anil Umesh, Kohei Kiyoshima, Tadashi Uchiyama
  • Patent number: 8897284
    Abstract: A radio base station (eNB) according to the present invention includes: an RI acquisition unit (11) configured to acquire, from a mobile station (UE), an “RI” indicating number of streams determined by the mobile station (UE); an adjustment unit (12) configured to adjust the “RI” acquired by the RI acquisition unit (11), by using an offset value “RI offset” unique to the mobile station (UE); and a stream-number determination unit (13) configured to determine the number of streams to be simultaneously transmitted to the mobile station (UE), based on the “RI” adjusted by the adjustment unit (12).
    Type: Grant
    Filed: December 15, 2009
    Date of Patent: November 25, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshiaki Ofuji, Naoto Okubo
  • Publication number: 20140226604
    Abstract: A base station 100 includes a scheduling processing unit 109 configured to schedule each of multiple mobile stations to the PDCCH, and a UE-type judgment unit 107 configured to judge whether each of the mobile stations is an OLD UE supporting only CFI=1 to 3 or a NEW UE supporting CFI=1 to 4. The scheduling processing unit 109 schedules each of the multiple UEs to the PDCCH by use of any one of CFI=1 to 3 when UEs targeted to be scheduled to the PDCCH include an OLD UE.
    Type: Application
    Filed: September 6, 2012
    Publication date: August 14, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Naoto Ookubo, Yoshiaki Ofuji
  • Publication number: 20140226603
    Abstract: A base station 100 includes a scheduling processing unit 109 configured to schedule multiple mobile stations to the PDCCH, and a UE-type judgment unit 107 configured to judge whether each of the mobile stations is an OLD UE supporting only CFI=1 to 3 or a NEW UE supporting CFI=1 to 4. For a first subframe, the scheduling processing unit 109 schedules the OLD UE to the PDCCH by use of any one of CFI=1 to 3. For a second subframe different from the first subframe, the scheduling processing unit 109 schedules the NEW UE to the PDCCH by use of any one of CFI=1 to 4.
    Type: Application
    Filed: September 6, 2012
    Publication date: August 14, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Naoto Ookubo, Yoshiaki Ofuji
  • Publication number: 20140219180
    Abstract: A base station 100 maps the system information formed of multiple blocks (SIB) to predetermined regions of a downlink shared channel and transmits the mapped system information to the mobile station. The base station 100 includes: a system information transmission control unit 105 configured to divide each of the predetermined regions into a first half and a second half in a time direction; and a transmission data generation unit 111 configured to map the system information to at least one of the first half and the second half. The system information transmission control unit 105 switches positions of the first half and the second half in rotation every transmission timing of the predetermined regions on the shared channel.
    Type: Application
    Filed: August 3, 2012
    Publication date: August 7, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Yoshiaki Ofuji, Naoto Ookubo
  • Publication number: 20140220989
    Abstract: A base station 100 includes: an external interface 101 configured to acquire the number of transmissions of the system information to the mobile station; a table holding unit 107 configured to hold a table in which a payload size of the system information, the number of transmissions, and the number of radio resource blocks corresponding to a combination of the payload size and the number of transmissions are associated with one another; a system information transmission control unit 105 configured to determine radio resource blocks required for the transmission of the system information, on the basis of the table held in the table holding unit 107; and a transmission data generation unit 111 configured to map the system information to predetermined regions of the shared channel by using the radio resource blocks determined by the system information transmission control unit 105.
    Type: Application
    Filed: August 3, 2012
    Publication date: August 7, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Yoshiaki Ofuji, Naoto Ookubo
  • Publication number: 20140204741
    Abstract: A base station 100 includes: a parameter control unit 103 configured to select either a normal control parameter used during normal time or an emergency control parameter used during an emergency where the number of voice calls to be handled increases from the number during normal time; and a scheduling unit 105 configured to schedule a PDSCH for a mobile station 200A based on either the normal control parameter or the emergency control parameter selected by the parameter control unit 103. The normal and emergency control parameters allow the number of voice calls processable by the base station 100 to change, and the emergency control parameter increases the number of processable voice calls to a number larger than that of the normal control parameter.
    Type: Application
    Filed: August 21, 2012
    Publication date: July 24, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Naoto Ookubo, Yoshiaki Ofuji, Sadayuki Abeta
  • Patent number: 8670431
    Abstract: A disclosed base station is used in a radio communication system where sounding reference signals from user terminals are multiplexed using distributed FDMA in which distributed frequency blocks each including frequency subcarriers discretely distributed in a system bandwidth are allocated to the user terminals, and the system bandwidth is repeatedly halved into frequency band segments according to a binary-tree structure.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: March 11, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshiaki Ofuji, Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20130315182
    Abstract: A base station of a mobile communication system includes a scheduler that generates uplink grant information indicating that uplink radio resources are allocated to less than or equal to a first multiplexing number of units of user equipment, a transmitter that transmits a control signal including the uplink grant information to the user equipment, and a receiver that receives an uplink signal which is transmitted by the user equipment. When a second multiplexing number being less than the first multiplexing number or more units of the user equipment exist which transmit periodically generated periodic data, and when the user equipment exists which transmits non-periodic data generated at non-periodic timing, the scheduler generates the uplink grant information indicating that the uplink radio resources are allocated to the second multiplexing number of the units of the user equipment that transmit periodic data and to the user equipment that transmits non-periodic data.
    Type: Application
    Filed: April 4, 2012
    Publication date: November 28, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Rika Kitou, Kohei Kiyoshima, Naoto Ookubo, Hiroyuki Ishii, Yoshiaki Ofuji, Mikio Iwamura, Anil Umesh
  • Patent number: 8594117
    Abstract: A base station in a mobile communications system which uses a single-carrier technique for uplink includes a classifying unit which classifies, for each of multiple user apparatuses according to a path loss between the respective user apparatus and the base station, the multiple user apparatuses into two or more groups; and a scheduler which plans allocating of uplink resources to the user apparatuses. Uplink signals of each user apparatus that have multiple frequency components lined up in equal frequency intervals are multiplexed using a distributed frequency division multiplexing technique such that they are made mutually orthogonal on a frequency axis, the scheduler plans the resource allocating such that the user apparatuses belonging to different groups utilize different group bands or different time slots, and the group bands are specified by dividing a system band into groups.
    Type: Grant
    Filed: June 13, 2007
    Date of Patent: November 26, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshiaki Ofuji, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi, Seizo Onoe
  • Publication number: 20130308592
    Abstract: A base station in a mobile communication system includes: a quality information obtaining unit configured to obtain quality information indicating a radio channel state of a user apparatus; an assignment period selection unit configured to select an assignment period corresponding to the quality information of the user apparatus from a predetermined correspondence relationship between each of a plurality of choices of assignment periods for assigning radio resources to periodic data that occurs periodically and a value of quality information indicating a radio channel state; a scheduling unit configured to determine radio resources to be assigned to the user apparatus in the assignment period that is selected; and a radio communication unit configured to communicate, by radio, user data including periodic data of the user apparatus by using the radio resources determined by the scheduling unit.
    Type: Application
    Filed: April 24, 2012
    Publication date: November 21, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Rika Kitou, Kohei Kiyoshima, Naoto Ookubo, Hiroyuki Ishii, Yoshiaki Ofuji, Mikio Iwamura, Anil Umesh
  • Publication number: 20130301602
    Abstract: A base station in a mobile communication system includes a scheduling unit generating downlink grant information indicating that downlink radio resources should be allocated to not more than a first multiplex number of user devices; and a transmission unit transmitting control signals containing the downlink grant information and data signals mapped to the radio resources specified by the downlink grant information, wherein, when less than the first multiplex number and not less than a second multiplex number being less than the first multiplex number, of user devices that receive periodically generated periodic data as data signals exist, and user devices that receive non-periodically generated non-periodic data as data signals exist, the scheduling unit generates downlink grant information indicating that the downlink radio resources should be allocated to the second multiplex number of user devices receiving the periodic data and the user devices receiving the non-periodic data.
    Type: Application
    Filed: April 6, 2012
    Publication date: November 14, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Mikio Iwamura, Yoshiaki Ofuji, Hiroyuki Ishii, Anil Umesh, Naoto Ookubo, Kohei Kiyoshima
  • Publication number: 20130286995
    Abstract: A base station of a communication system includes a quality information retrieval unit that retrieves quality information indicating a radio channel state of user equipment, a threshold value determination unit that determines, for each of the user equipment, a threshold value for at least one of a data retention amount and a data retention time period, depending on the quality information, a scheduler that calculates a scheduling coefficient for the user equipment for which at least the one of the data retention amount and the data retention time period exceeds the threshold value, and that allocates a radio resource to the user equipment at least in accordance with a magnitude of the scheduling coefficient, and a notification unit that reports to the user equipment that the radio resource is allocated.
    Type: Application
    Filed: March 12, 2012
    Publication date: October 31, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Tooru Uchino, Mikio Iwamura, Yoshiaki Ofuji, Hiroyuki Ishii, Anil Umesh, Naoto Ookubo, Kohei Kiyoshima
  • Patent number: 8520608
    Abstract: A mobile communication system in which a finite number of reference signal sequences used for uplink channel estimation or the like are reused among multiple cells includes a determining unit configured to determine a frequency band used by user terminals to which a reference signal sequence with a predetermined sequence length is assigned in each of the cells within an interference area, wherein the frequency band is determined to be different from frequency bands used in the other cells.
    Type: Grant
    Filed: June 14, 2007
    Date of Patent: August 27, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshiaki Ofuji, Kenichi Higuchi, Mamoru Sawahashi