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: 8125887
    Abstract: An object of the present invention is to reduce the amount of calculation performed in a mobile station and amount of information exchanged between a base station and mobile station in a mobile communication system where the base station autonomously assigns a scramble code. In the mobile communication system, the base station starts communication by using a predetermined initialization scramble code used only at its activation time. The mobile station positioned in a cell determines whether the scramble code identified upon cell search time is the initialization scramble code. Only when the scramble code is the initialization scramble code, the mobile station determines a candidate scramble code, determines whether the candidate scramble code is usable in communication, and notifies the base station of the control information including the determination result.
    Type: Grant
    Filed: March 1, 2007
    Date of Patent: February 28, 2012
    Assignee: NEC Corporation
    Inventors: Takamichi Inoue, Yoshikazu Kakura
  • Patent number: 8121105
    Abstract: In a radio communication system, transmission of CAZAC sequences as the pilot signal sequences by using code division multiplexing as at least one of user multiplexing schemes, is done by dividing a system band as a frequency band usable in the system into frequency blocks B1 and B2 having bandwidths W1 and W2, generating the pilot signals of the frequency blocks B1 and B2 with a single carrier, using the pilot signal sequences having sequence lengths L1 and L2 corresponding to frequency blocks B1 and B2 respectively; and, transmitting the generated pilot signals as the pilot signals corresponding individual users, with multicarriers using an arbitrary number of frequency blocks among the plural frequency blocks.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: February 21, 2012
    Assignee: NEC Corporation
    Inventors: Takamichi Inoue, Yoshikazu Kakura
  • Publication number: 20120026962
    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: Application
    Filed: March 19, 2010
    Publication date: February 2, 2012
    Applicant: NEC CORPORATION
    Inventors: Takamichi Inoue, Kenji Koyanagi, Yoshikazu Kakura
  • Publication number: 20120009962
    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: Application
    Filed: December 22, 2008
    Publication date: January 12, 2012
    Applicant: NEC CORPORATION
    Inventors: Le Liu, Yoshikazu Kakura
  • Publication number: 20120008615
    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 is characterized by using a different signal sequence in each of the carriers, and using the signal sequences as reference signals. 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: Application
    Filed: March 19, 2010
    Publication date: January 12, 2012
    Applicant: NEC CORPORATION
    Inventors: Takamichi Inoue, Kenji Koyanagi, Yoshikazu Kakura
  • Publication number: 20110235604
    Abstract: Provided is a technique for efficiently selecting access schemes for use in communications. This invention includes an identifying means that identifies, from station-on-the-other-end candidate information, which is control information in which information related to an access scheme corresponding to each of a plurality of stations-on-the-other-end of communication is described, and from information related to an access scheme corresponding to the local station, access schemes beforehand one of which can be used in communication with a communication partner station; and a selecting means that selects, as the access scheme to be used in data communication with a communication partner station, one of the identified access schemes when the data communication is started.
    Type: Application
    Filed: November 24, 2009
    Publication date: September 29, 2011
    Applicant: NEC CORPORATION
    Inventors: Takamichi Inoue, Yoshikazu Kakura
  • Patent number: 8027400
    Abstract: In a transmitting portion of a wireless communication apparatus, hopping pattern generating portions 16 and 17 produce hopping patterns independent from each other and specific to a transmitter. Subcarrier assigning portions 18 and 19 assign transmission symbol sequences to subcarriers 1 to R in accordance with the hopping patterns and produce frequency hopping signals. In a receiving portion of the wireless communication apparatus, a MIMO demodulating portion 37 combines and decomposes a FFT signal and produces a demodulated signal. Hopping pattern generating portions 38 and 39 produce unique hopping patterns corresponding to transmitters 1-1 to 1-K, respectively. Subcarrier extracting portions 40 and 41 extract, from the demodulated signal, components corresponding to the hopping patterns and produce the components as partial demodulated sequences, respectively.
    Type: Grant
    Filed: December 24, 2004
    Date of Patent: September 27, 2011
    Assignee: NEC Corporation
    Inventor: Yoshikazu Kakura
  • Publication number: 20110211538
    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.
    Type: Application
    Filed: August 4, 2008
    Publication date: September 1, 2011
    Applicant: NEC CORPORATION
    Inventor: Yoshikazu Kakura
  • Patent number: 7948957
    Abstract: A receiver connected to a plurality of reception antennas includes a propagation path correlation estimation circuit. The propagation path correlation estimation circuit calculates a correlation value of each propagation path between each of the transmission antennas and each of the reception antennas and transmits the calculation result as propagation path correlation information (SCOR). A transmitter connected to a plurality of transmission antennas includes a spread code assigning circuit. According to the propagation path correlation information, the spread code assigning circuit assigns only spread codes orthogonal to each other for the transmission antenna corresponding to a correlation value exceeding a threshold value and, for a transmission antenna having no propagation path of a correlation value exceeding the threshold value, assigns a spread code without considering orthogonality to a spread code in the other transmission antenna.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: May 24, 2011
    Assignee: NEC Corporation
    Inventor: Yoshikazu Kakura
  • Publication number: 20110113433
    Abstract: Provided is a technique capable of reporting resource block allocation information with no waste when an allocated resource block is reported, because in the current LTE downlink, the waste of the amount of resource allocation information increases in some cases since a restriction is imposed such that 37-bit fixed scheduling information is transmitted. A resource block group consisting of at least one or more resource blocks continuous on the frequency axis is allocated to a terminal, and the number of controlling signals for reporting allocation information indicating the allocated resource blocks is determined.
    Type: Application
    Filed: June 19, 2009
    Publication date: May 12, 2011
    Applicant: NEC CORPORATION
    Inventors: Kenji Koyanagi, Takamichi Inoue, Le Liu, Yoshikazu Kakura
  • Publication number: 20110110322
    Abstract: To solve a problem that although the increase of the number of frequency blocks by allocating discontinuous subcarriers (RBs) as in OFDM enables an increase in multi-diversity effect and an improvement in throughput, the number of RB allocation patterns increases with the increase of the number of frequency blocks, resulting in an increase in the amount of information relating to the allocated RBs, the resource block allocation unit is determined when resource blocks discontinuous on the frequency axis are allocated to a terminal, and the number of bits of scheduling information indicating the allocated resource blocks by using Tree Based is set to the number of bits corresponding to the determined allocation unit.
    Type: Application
    Filed: June 19, 2009
    Publication date: May 12, 2011
    Applicant: NEC CORPORATION
    Inventors: Kenji Koyanagi, Takamichi Inoue, Le Liu, Yoshikazu Kakura
  • Patent number: 7936838
    Abstract: It is an object to provide a receiving apparatus which is capable of demodulating signals with a very simple arrangement. Receiving apparatus 1 has N reception antennas 11-1-11-N, and reception antennas 11-1-11-N receive signals. Channel coefficient estimator 12 estimates and outputs channel coefficients from the signals received by respective reception antennas 11-1-11-N. QR decomposer 13 is supplied with a channel matrix having the channel coefficients as its elements, performs QR decomposition on the channel matrix, and outputs a Q matrix and an R matrix. A QH processor 14 is supplied with the Q matrix and the received signals, multiplies the received signals by a complex conjugate transposed matrix of the Q matrix, and outputs converted signal z. A transmitted sequence estimator 15 is supplied with converted signal z and the R matrix and estimates transmitted sequences.
    Type: Grant
    Filed: February 14, 2005
    Date of Patent: May 3, 2011
    Assignees: NEC Corporation, Fujitsu Limited, NTT DoCoMo, Inc.
    Inventors: Takumi Ito, Shousei Yoshida, Yoshikazu Kakura, Hiroyuki Seki, Hiroyuki Kawai, Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20110002282
    Abstract: The problem is that, in a mobile wireless system, when more than one frequency block composed of resource blocks that are consecutive on a frequency axis is assigned to one mobile station, the multi-diversity effect due to scheduling increases by the number of assigned frequency blocks being increased, but the overhead caused by the scheduling information increases. Accordingly, there is a tradeoff between the multi-diversity effect and the scheduling overhead. However, when the aforementioned tradeoff was considered with OFDM and SC-FDMA, the same fixed number of frequency blocks would have been used for all mobile stations. Accordingly, an optimization that takes into account the tradeoff between the multi-diversity effect and scheduling overhead has not been sufficiently achieved.
    Type: Application
    Filed: March 18, 2009
    Publication date: January 6, 2011
    Inventors: Takamichi Inoue, Kenji Koyanagi, Le Liu, Yoshikazu Kakura
  • Publication number: 20100329199
    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: Application
    Filed: March 16, 2009
    Publication date: December 30, 2010
    Inventors: Le Liu, Kenji Koyanagi, Takamichi Inoue, Yoshikazu Kakura
  • Publication number: 20100300915
    Abstract: The present invention relates to a wet sheet flexible package 1, including a plurality of wet sheets 2 impregnated with a liquid; a film bag 3 that is a flexible film bag packaging the plurality of wet sheets 2 and including a dispensing opening 31; and a label 5 attached to a surface of the film bag 3, covering the dispensing opening 31, and being able to be peeled off. In the wet sheet flexible package 1, when the label 5 is peeled off from the film bag 3, the dispensing opening 31 is unsealed and an adhesive layer 53 is exposed around the dispensing opening 51 on the surface of the film bag 3. A substrate 54 is provided between the adhesive layer 53 and the surface of the film bag 3, and the substrate 54 is composed of a film having a higher compression strength than a film composing the film bag 53.
    Type: Application
    Filed: October 31, 2008
    Publication date: December 2, 2010
    Inventors: Yoshikazu Kakura, Akihisa Watanabe, Eiji Yamamoto, Takeshi Bandoh
  • Patent number: 7826514
    Abstract: A radio transmitter-receiver wherein a pilot symbol is used in the transmitter that has undergone M-chip spreading on the frequency axis and N-chip spreading on the time axis by a spreading code of M×N chip length (where M and N are any integers equal to or greater than 2), and in the receiver, a spreading code that is not used in spreading said pilot signal is used as a despreading code to despread a received signal and then estimate noise and interference power. The spreading code that is used to spread the pilot symbol and the despreading code that is used in despreading are assigned so as to be orthogonal even if only in N chips on the time axis.
    Type: Grant
    Filed: April 26, 2004
    Date of Patent: November 2, 2010
    Assignees: NEC Corporation, NTT DoCoMo, Inc.
    Inventors: Yoshikazu Kakura, Shousei Yoshida, Hiroyuki Atarashi, Noriyuki Maeda
  • Patent number: 7822132
    Abstract: N sub-carriers are grouped in units of predetermined quantities in order beginning with the one exhibiting the highest communication channel quality to generate an optimal group pattern on the reception side. Then, communication channel information is calculated for each of sub-carrier groups in the optimal group pattern or a quasi-optimal group pattern which is assumed to be closest to the optimal group pattern among a plurality of previously set group pattern candidates. Communication channel information is designated as modified communication channel information. Grouping information indicative of the optimal group pattern or quasi-optimal group pattern is combined with modified communication channel information to generate feedback information. On the transmission side, sub-carriers are grouped based on reproduced feedback information reproduced from the feedback information.
    Type: Grant
    Filed: October 31, 2005
    Date of Patent: October 26, 2010
    Assignee: NEC Corporation
    Inventors: Hisashi Futaki, Yoshikazu Kakura, Shousei Yoshida, Takumi Ito
  • Patent number: 7746807
    Abstract: A receiver estimates a channel quality. A transmitter amplifies a signal by a gain proportional to a difference between a required signal-to-noise power ratio and channel quality information, which is an estimation result of the channel quality, and transmits the signal so that the receiver can obtain the signal-to-noise power ratio. In this case, the receiver or the transmitter determines a roll-off rate of an adaptive filter based on the channel quality information. The transmitter uses the adaptive filter of the determined roll-off rate to filter and transmit the signal.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: June 29, 2010
    Assignee: NEC Corporation
    Inventors: Yoshikazu Kakura, Shousei Yoshida, Kengo Oketani
  • Publication number: 20100157885
    Abstract: There is provided a radio communication system in which a mobile station which has decided to switch a base station can immediately be synchronized with the base station to which switching is to be made. Each of the base stations creates a synchronization signal for the mobile station to synchronize with the base station from an upstream pilot signal received from the mobile station, creates upstream propagation quality information from the upstream pilot signal, and creates a downstream control signal including the synchronization information and the upstream propagation quality information, and transmits them.
    Type: Application
    Filed: August 22, 2006
    Publication date: June 24, 2010
    Applicant: NEC CORPORATION
    Inventors: Kenji Koyanagi, Yoshikazu Kakura, Jinsock Lee, Nahoko Kuroda
  • Patent number: 7668076
    Abstract: A multi-user receiving apparatus is provided for achieving a reduction in the amount of processing for single-carrier FDMA signals and an improvement in reception characteristics. A DFT unit converts single-carrier FDMA received signals of all users to signals in a frequency domain commonly. A demapping unit selects part of sub-carriers for each user from sub-carriers supplied from the DFT unit. A reception filter separates a user signal and suppresses noise. A demodulator demodulates the user signal, and detects a timing thereof.
    Type: Grant
    Filed: September 22, 2006
    Date of Patent: February 23, 2010
    Assignee: NEC Corporation
    Inventors: Shousei Yoshida, Masayuki Kimata, Yoshikazu Kakura, Kengo Oketani