Patents by Inventor Yoshikazu Kakura

Yoshikazu Kakura 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: 8953533
    Abstract: Provided is a wireless communication technique capable of supporting communication using a single component carrier, and communication using a plurality of component carriers. The communication using the plurality of carriers comprises a processing means for performing the signal processing in accordance with each of the carriers with respect to the common signal sequence used by the plurality of carriers. The present invention makes it possible to cope with the communication employing a single component carrier and the wireless communication employing a plurality of the component carriers. Further, PAPR of the reference signals can be made small because there is no possibility that the identical CAZAC sequence is used among the component carriers when a plurality of the component carriers are employed.
    Type: Grant
    Filed: March 19, 2010
    Date of Patent: February 10, 2015
    Assignee: NEC Corporation
    Inventors: Takamichi Inoue, Kenji Koyanagi, Yoshikazu Kakura
  • Publication number: 20150031284
    Abstract: A communication system and method that can minimize interference between RN-access links and can maximize the capacity of RNs in the network is provided. The communication system has a plurality of communication nodes which includes a base station and a plurality of relay nodes, wherein the base station controls the relay nodes, each of which can provide a radio connection to at least one terminal via an access link, wherein the base station signals each of the relay nodes to report measurement information related to the access link.
    Type: Application
    Filed: February 21, 2013
    Publication date: January 29, 2015
    Applicant: NEC CORPORATION
    Inventors: Boonsarn Pitakdumrongkija, Yoshikazu Kakura, Naoto Ishii
  • Publication number: 20150009888
    Abstract: A communication system and method that allows a DeNB to identify a RN registered to another DeNB and to acquire necessary information for coordinating interference from RNs registered to the other DeNB are provided. The communication system includes a plurality of communication nodes which includes a plurality of base stations and a plurality of relay nodes, wherein each relay node has a radio connection with a base station, wherein each base station exchanges information indicating identity of a relay node with another base station.
    Type: Application
    Filed: February 21, 2013
    Publication date: January 8, 2015
    Applicant: NEC Corporation
    Inventors: Boonsam Pitakdumrongkija, Yoshikazu Kakura, Naoto Ishii
  • Publication number: 20150003362
    Abstract: A method for controlling reporting setting that enables reporting setting to be changed quickly in a system where CoMP transmission is performed, as well as a wireless communications system using the same are provided. In a wireless communications system based on a coordinated transmission scheme in which multiple transmission stations included in a network perform transmission in coordination with each other, the network notifies multiple pieces of reporting setting information for channel state information to a reception station that is a target of the coordinated transmission scheme, and the transmission stations and the reception station share reporting setting information to be applied among the multiple pieces of reporting setting information.
    Type: Application
    Filed: January 24, 2013
    Publication date: January 1, 2015
    Applicant: NEC CORPORATION
    Inventors: Takamichi Inoue, Kojiro Hamabe, Yoshikazu Kakura, Naoto Ishii, Le Liu
  • Patent number: 8923871
    Abstract: A mobile communication system includes a base station and a relay station. The relay station acquires a donor cell list indicating at least one candidate cell that can be used for a backhaul link. The relay station or the base station determine a donor cell used for the backhaul link from the donor cell list based on both first and second cell management information. The first cell management information relates to the at least one candidate cell and originates from the at least one base station. The second cell management information originates from the relay station.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: December 30, 2014
    Assignee: NEC Corporation
    Inventors: Hiroaki Aminaka, Yoshikazu Kakura
  • Patent number: 8891493
    Abstract: A reference signal sequence assignment method and device are provided by which the influence of inter-cell interference can be reduced and the number of usable cyclic shifted sequences per sector can be increased. In a mobile communications system with a structure including multiple cells each including multiple sectors, a sequence assignment method is employed by which pseudo-orthogonal sequences used for reference signals are assigned to cells or sectors. According to this method, the multiple pseudo-orthogonal sequences are assigned to cells or sectors by using multiple repetition patterns.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: November 18, 2014
    Assignee: NEC Corporation
    Inventors: Takamichi Inoue, Yoshikazu Kakura
  • Patent number: 8885597
    Abstract: A radio communication system includes a plurality of base stations with supporting a plurality of radio access schemes. Two or more base stations support a predetermined radio access scheme in common. A mobile station makes initial connection to one of the two or more base stations according to the predetermined radio access scheme, to allow communication with the one base station.
    Type: Grant
    Filed: April 7, 2009
    Date of Patent: November 11, 2014
    Assignee: NEC Corporation
    Inventors: Kenji Koyanagi, Hisashi Futaki, Yoshikazu Kakura
  • Publication number: 20140307709
    Abstract: There is provided a wireless communication system which can synchronize a mobile station with a destination base station in response to the mobile station determining to switch base stations. Each base station generates synchronization information to synchronize the mobile station with the base station from a reverse pilot signal received from the mobile station, generates reverse propagation quality information from the reverse pilot signal, and generates and transmits a control signal including the synchronization information and the reverse propagation quality information. A mobile station generates and transmits a reverse pilot signal, receives a signal including the control signal from each of the base stations.
    Type: Application
    Filed: June 10, 2014
    Publication date: October 16, 2014
    Applicant: NEC CORPORATION
    Inventors: Kenji KOYANAGI, Yoshikazu KAKURA, Jinsock LEE, Nahoko KURODA
  • Patent number: 8812040
    Abstract: This invention has been accomplished in consideration of problems, and an object thereof is to provide a technology that enables a maximum transmit power suitable for each user equipment. This invention is a communication system, is characterized in deciding a maximum value of a transmit power of a user equipment by employing at least one of an access scheme and control information indicating a content of a communication control.
    Type: Grant
    Filed: December 22, 2008
    Date of Patent: August 19, 2014
    Assignee: NEC Corporation
    Inventors: Le Liu, Yoshikazu Kakura
  • Patent number: 8797964
    Abstract: There is provided a wireless communication system which can synchronize a mobile station with a destination base station in response to the mobile station determining to switch base stations. Each base station generates synchronization information to synchronize the mobile station with the base station from a reverse pilot signal received from the mobile station, generates reverse propagation quality information from the reverse pilot signal, and generates and transmits a control signal including the synchronization information and the reverse propagation quality information. A mobile station generates and transmits a reverse pilot signal, receives a signal including the control signal from each of the base stations.
    Type: Grant
    Filed: July 9, 2012
    Date of Patent: August 5, 2014
    Assignee: NEC Corporation
    Inventors: Kenji Koyanagi, Yoshikazu Kakura, Jinsock Lee, Nahoko Kuroda
  • Patent number: 8774022
    Abstract: A scheduling technique for limiting a discontinuous spectrum to reduce control information to be transmitted from a base station (BS) to each of mobile stations. The method has a ranking means for ranking the mobile stations for each resource block depending on the channel status, and an allocation means for allocating the resource blocks to the mobile stations depending on the ranking of the mobile stations so that the number of resource blocks in a resource block group for one mobile station may be not more than a set number. The resource block group including at least one or more continuous resource blocks on the frequency axis.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: July 8, 2014
    Assignee: NEC Corporation
    Inventors: Le Liu, Kenji Koyanagi, Takamichi Inoue, Yoshikazu Kakura
  • Publication number: 20140003544
    Abstract: A memory 21 of a pilot processing circuit 2 holds in advance a pilot sequence converted into a frequency region signal obtained by subjecting a pilot signal symbol transmitted in one block to Ntx_p-point DFT. The pilot sequence held in the memory 21 is subjected to a series of processes including a roll-off filtering by a roll-off filter circuit 22, subcarrier mapping process by subcarrier mapping circuit 23, an Ndft_p-point IDFT operation by an IDFT circuit 24, and a cyclic prefix adding process by a cyclic prefix adding circuit 25.
    Type: Application
    Filed: August 30, 2013
    Publication date: January 2, 2014
    Applicant: NEC CORPORATION
    Inventors: Kengo OKETANI, Yoshikazu KAKURA, Toshifumi SATO, Shousei YOSHIDA
  • Patent number: 8594039
    Abstract: A reference signal of a user equipment to which a resource (LB#1) is allocated for a L1/L2 control signal, is allocated a resource (SB#1) that is closer on the time axis to the resource (LB#1), which the L1/L2 control signal is allocated, within the same frequency band as the L1/L2 control signal. A reference signal for CQI estimation, independent of a data signal and a L1/L2 control signal, is allocated a resource with which at least one of a reference signal for demodulation of a data signal and a reference signal for demodulation of a L1/L2 control signal is not transmitted at the same timing within the transmission band. The types of bandwidths of the reference signals multiplexed in a same short block within a same band are reduced, whereby restrictions as to the number of reference signal sequences that can be secured are diminished.
    Type: Grant
    Filed: August 20, 2007
    Date of Patent: November 26, 2013
    Assignee: NEC Corporation
    Inventors: Yoshikazu Kakura, Shousei Yoshida, Takamichi Inoue
  • Publication number: 20130272246
    Abstract: A device and method in which a plurality of Zadoff-Chu sequences is allocated to a frame, a value of a parameter in the Zadoff-Chu sequence is different among the plurality of Zadoff-Chu sequences, and the Zadoff-Chu sequence allocated to the frame is different among a plurality of cells.
    Type: Application
    Filed: June 11, 2013
    Publication date: October 17, 2013
    Inventors: Kengo OKETANI, Yoshikazu Kakura
  • Patent number: 8548008
    Abstract: A memory 21 of a pilot processing circuit 2 holds in advance a pilot sequence converted into a frequency region signal obtained by subjecting a pilot signal symbol transmitted in one block to Ntx_p-point DFT. The pilot sequence held in the memory 21 is subjected to a series of processes including a roll-off filtering by a roll-off filter circuit 22, subcarrier mapping process by subcarrier mapping circuit 23, an Ndft_p-point IDFT operation by an IDFT circuit 24, and a cyclic prefix adding process by a cyclic prefix adding circuit 25.
    Type: Grant
    Filed: February 7, 2007
    Date of Patent: October 1, 2013
    Assignee: NEC Corporation
    Inventors: Kengo Oketani, Yoshikazu Kakura, Toshifumi Sato, Shousei Yoshida
  • Patent number: 8520611
    Abstract: A communication system comprises a base station and a mobile station. The base station has resource allocating means for associating basic resources which are M unit resources (M is two or more integer) of a first control channel through which first control information is transmitted with the resources of a second control channel through which second control information is transmitted, allocating at least a part of the basic resources to the first control information, and associating the first control information with the resources of the second control channel corresponding to one of the basic resources allocated to the first control information and first control information transmitting means for transmitting the allocated first control information to the mobile station. The mobile station has second control information transmitting means for receiving the first control information and transmitting second control information by using the resources of the second control channel.
    Type: Grant
    Filed: August 4, 2008
    Date of Patent: August 27, 2013
    Assignee: NEC Corporation
    Inventor: Yoshikazu Kakura
  • Patent number: 8509262
    Abstract: A mobile station in a communication system including a base station, the mobile station includes a unit for sending a signal that allocates a plurality of different Zadoff-Chu sequences to a frame to the base station.
    Type: Grant
    Filed: August 13, 2012
    Date of Patent: August 13, 2013
    Assignee: NEC Corporation
    Inventors: Kengo Oketani, Yoshikazu Kakura
  • Publication number: 20130196678
    Abstract: A scheduling system for coordinated user equipments (UEs) in a network including a plurality of communicating points which can communicate with each other, wherein the coordinated UEs are supported by a serving point and are coordinated with a neighbor point, is characterized in that the serving point and the neighbor point share information related to an available or desired amount of resources for coordinated UEs of the serving point; and the serving point adjusts at least one predetermined parameter related to the coordinated UEs based on the shared information so that the amount of resources for the coordinated UEs at the serving point approaches the available or desired amount of resources for the coordinated UEs at the neighbor point.
    Type: Application
    Filed: October 7, 2010
    Publication date: August 1, 2013
    Applicant: NEC CORPORATION
    Inventors: Le Liu, Takamichi Inoue, Yoshikazu Kakura
  • Patent number: 8477754
    Abstract: A wireless communication apparatus is provided that is capable of achieving both the suppression of interference between base stations and the capability to track mobile stations that are moving at a high speed. A moving speed estimating unit estimates the moving speed of each mobile station based on reception signals. A directivity determining unit determines reception antenna directivity for each mobile station based on the reception signals and the estimated moving speeds. A signal separating unit separates the reception signals into signal components that have been transmitted from respective mobile stations, based on the directivities. A signal recovering unit recovers transmission signals from respective mobile stations based on the respective signal components. A resource assigning unit determines radio resource assignments of transmission signals to the respective mobile stations based on a service quality signal and the estimated moving speed.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: July 2, 2013
    Assignee: NEC Corporation
    Inventor: Yoshikazu Kakura
  • Patent number: 8428157
    Abstract: To provide a reference signal generation method and apparatus capable of obtaining many reference signal sequences having excellent properties. CAZAC sequences that satisfy the condition that the absolute value (|N?L|) of a difference between a sub-carrier number N in a resource block and a CAZAC sequence length L is not larger than a threshold value K are selected, and a sequence having a largest among greatest prime factors among the prime factors constituting the sequence length(s) is further selected from the initially selected sequences. Then, a reference signal sequence(s) is generated from a selected CAZAC sequence.
    Type: Grant
    Filed: January 31, 2008
    Date of Patent: April 23, 2013
    Assignee: NEC Corporation
    Inventors: Yoshikazu Kakura, Kengo Oketani