Patents by Inventor Mamoru Sawahashi

Mamoru Sawahashi 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: 8498235
    Abstract: A communication apparatus in a mobile communication system includes a first control information generation unit configured to generate first control information including retransmission information on a previously received data channel, a second control information generation unit configured to generate second control information including scheduling information on radio resources and a transmission signal generation unit configured to generate a transmission signal including a lower layer control channel including at least one of the first control information and the second control information. The transmission signal generation unit generates the transmission signal to transmit the first control information in any of subframes arriving at a first cycle and to transmit the second control information in any of subframes arriving at a second cycle longer than the first cycle.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: July 30, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Mamoru Sawahashi
  • Patent number: 8498663
    Abstract: A base station includes: means that derives a transmission power of a mobile station based on receive quality of an uplink pilot channel; means that reports the derived transmission power to the mobile station; and means that receives a control channel transmitted by the mobile station according to the reported information. Accordingly, irrespective of transmission power history over a past continuous time, the mobile station receives an instruction on the transmission power from the base station each time when transmitting a packet so as to be able to adjust the transmission power.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: July 30, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Hiroyuki Atarashi, Mamoru Sawahashi
  • Patent number: 8498347
    Abstract: A transmission apparatus used in a mobile communication system adopting a single carrier scheme in an uplink includes: multiplexing means configured to multiplex a pilot channel, a control channel, and a data channel; and transmission means configured to transmit a transmission symbol including at least the pilot channel and the control channel using the uplink. A first pilot channel used for a reception apparatus to measure channel state of the uplink is transmitted using a frequency band over a plurality of resource blocks. A second pilot channel for compensating for a channel transmitted by the uplink is transmitted by a resource block assigned to the transmission apparatus. Control channels of the transmission apparatus and the apparatus other than the transmission apparatus are orthogonalized with each other by a FDM scheme.
    Type: Grant
    Filed: April 19, 2007
    Date of Patent: July 30, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20130188596
    Abstract: A base station communicates with a user device transmitting an uplink signal based on a single-carrier transmission scheme. The base station includes a frequency hopping determining unit configured to determine whether to apply frequency hopping to the user device based on radio-wave propagation information from the user device and a traffic type of data to be transmitted by the user device; a scheduler configured to allocate frequencies to the user device based on uplink channel reception conditions of the user device; and a reporting unit configured to report allocation information indicating resource units allocated by the scheduler to the user device. When the frequency hopping determining unit determines to apply the frequency hopping to the user device, the scheduler allocates, to the user device, resource units with different frequency bands in different slots.
    Type: Application
    Filed: March 8, 2013
    Publication date: July 25, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8488528
    Abstract: User equipment for performing cell search using a synchronization channel including a primary synchronization channel and a secondary synchronization channel includes a reception unit configured to receive a signal including the synchronization channel, a symbol timing candidate detection unit configured to detect multiple synchronization signal symbol timing candidates from the synchronization channel based on a correlation value in a time domain between the signal received at the reception unit and a replica signal of the primary synchronization channel, a secondary synchronization channel correlation detection unit configured to perform correlation detection for the secondary synchronization channel based on the multiple synchronization signal symbol timing candidates detected in the symbol timing candidate detection unit and a secondary synchronization channel detection unit configured to detect the secondary synchronization channel based on a result of the correlation detection by the secondary synchroni
    Type: Grant
    Filed: August 7, 2009
    Date of Patent: July 16, 2013
    Assignee: NTT Docomo, Inc.
    Inventors: Satoshi Nagata, Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8488534
    Abstract: A base station includes a scheduler determining allocation of radio resources for each subframe; a control channel generating unit generating a control channel including common control information mapped across a system frequency band and specific control information mapped to one or more resource blocks allocated to a selected user device; and a transmission signal generating unit generating a transmission signal by time-division-multiplexing the common control information and the specific control information. The common control information is transmitted every subframe and includes information units with a predetermined data size, a format indicator representing one of preset options indicating the number of symbols occupied by the common control information, and information indicating the maximum number of the information units.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: July 16, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20130176931
    Abstract: A disclosed OFDM-based transmission device includes a unicast channel generating unit configured to generate a unicast channel; an MBMS channel generating unit configured to generate an MBMS channel; a multiplexing unit configured to time-division-multiplex the unicast channel and the MBMS channel in the same frequency band; and a transmitting unit configured to transmit time-division-multiplexed transmission symbols. In the disclosed transmission device, the guard interval length for the MBMS channel is set longer than the guard interval length for the unicast channel.
    Type: Application
    Filed: February 8, 2013
    Publication date: July 11, 2013
    Inventors: Kenichi Higuchi, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8483043
    Abstract: A transmitter includes: a data modulation and channel coding unit configured to perform data modulation and channel coding for a data channel with a modulation level and a channel coding rate updated for each transmission time interval; a multiplexing unit configured to multiplex a control channel and the data channel for each transmission time interval; and an adjusting means configured to adjust a length of the transmission time interval. Increasing a unit of information transmission in the time direction and/or the frequency direction depending on communication conditions can reduce a frequency of inserting (allocating) the control channel, and can improve data transmission efficiency.
    Type: Grant
    Filed: December 27, 2011
    Date of Patent: July 9, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventor: Mamoru Sawahashi
  • Patent number: 8483170
    Abstract: A user equipment terminal for reporting channel quality information to a base station includes a channel quality information measuring unit configured to measure channel quality information; and a channel quality information generating unit configured to generate, as the channel quality information, a difference value between a first absolute value of the measured channel quality information and a second absolute value of previously measured channel quality information. The present invention also relates to a base station and a channel quality information report method.
    Type: Grant
    Filed: August 13, 2008
    Date of Patent: July 9, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8478279
    Abstract: To set an optimal transmission power control interval such that a base station apparatus properly receives signals from a mobile station, while exploiting fast scheduling and fast AMC, in this closed-loop transmission power control method, reception SINR and average interference level are measured in a signal received in uplink, a time period for averaging reception quality is determined corresponding to an overlapped size of a dynamic range of a base station apparatus that is a region of overlapping a first reception-allowable range depend on reception capability of the base station apparatus, with a second reception-allowable range, varying corresponding to the interference level, depend on the number of a modulation and coding scheme set, each set achieving required throughput, the reception SINR is averaged using the determined time period, and a TPC command indicative of uplink transmission power to be controlled in a terminal apparatus is generated using a difference value between the averaged reception
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: July 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Daisuke Nishikawa, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8477696
    Abstract: The object is achieved by providing a transmission apparatus with: assignment means configured to assign, to each user, one of a frequency block that is obtained by dividing a system bandwidth into each block of continuous frequency subcarriers and a distributed type frequency block that include a frequency subcarrier that is discretely distributed in the system bandwidth; and mapping means configured to assign transmission data to one of the frequency block and the distributed type frequency block according to the assignment.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: July 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8477732
    Abstract: An apparatus determines a transmission bandwidth for uplink transmission of a signal and includes a reception unit that receives a predefined signal from a mobile station and derives a channel quality indicator based on the received signal. The apparatus also includes a storage unit that stores a relationship between the channel quality indicator and the transmission bandwidth of the mobile station. The apparatus also includes a determination unit that determines the transmission bandwidth based on the relationship and a transmission unit that transmits the transmission bandwidth to the mobile station.
    Type: Grant
    Filed: October 31, 2006
    Date of Patent: July 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Hiroyuki Atarashi, Mamoru Sawahashi
  • Patent number: 8477708
    Abstract: A base station includes: means configured to manage frequency blocks; means configured to determine, for each frequency block, scheduling information for assigning one or more resource blocks to a communication terminal being in a good channel state; means configured to generate a control channel including the scheduling information for each frequency block; and means configured to frequency multiplexing control channels within the system frequency band and to transmit it. In addition, the base station transmits the control channel by separating a non-specific control channel to be decoded by a non-specific communication terminal and a specific control channel to be decoded by a communication terminal to which one or more resource blocks are assigned.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: July 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Mamoru Sawahashi, Nobuhiko Miki, Yoshihisa Kishiyama
  • Patent number: 8477706
    Abstract: A transmission apparatus which attempts improvement of signal quality in an uplink and a downlink carries out radio transmission of different signals simultaneously from respective ones of a plurality of antennas. The apparatus has pilot multiplexing means for multiplexing a pilot channel to transmit from each antenna in one or more of a time division multiplexing method, a frequency division multiplexing method and a code division multiplexing method, data multiplexing means for time-multiplexing a pilot channel and a data channel, and means for transmitting a signal in a least one of a space division multiplexing (SDM) method and a space time transmission diversity (STTD) method.
    Type: Grant
    Filed: May 6, 2011
    Date of Patent: July 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Mamoru Sawahashi, Kenichi Higuchi, Hiroyuki Atarashi
  • Publication number: 20130163545
    Abstract: A disclosed base station apparatus is capable of communicating with a user equipment terminal in a multi-input multi-output (MIMO) mobile communication system using Pre-coding. The base station apparatus includes a receiving unit receiving a Pre-coding Matrix Indicator (PMI) indicating a specific Pre-coding matrix, a determination unit determining a value of a flag indicator indicating whether the Pre-coding matrix specified in the PMI is to be used for downlink communications, a control signal generation unit generating a downlink control signal including at least the flag indicator, and a transmission unit transmitting a signal including the downlink control signal in downlink.
    Type: Application
    Filed: February 14, 2013
    Publication date: June 27, 2013
    Inventors: Hidekazu Taoka, Nobuhiko Miki, Mamoru Sawahashi
  • Patent number: 8472548
    Abstract: Provided is a radio base station apparatus capable of selecting an optimal modulation and coding scheme for each transmission stream easily. The radio base station apparatus has a CQI information decoder (101) configured to decode CQIs of plural downlink transmission streams and an MCS selector (102) that has an N-dimensional table (two-dimensional reference table (1021)) in accordance with the number N of downlink transmission streams where combinations of modulation and coding scheme between the plural downlink transmission streams are defined in accordance with each of the CQIs of the downlink transmission streams and is configured to select from the combinations of modulation and coding scheme for the downlink transmission streams based on each of the CQIs of the downlink transmission streams decoded by the CQI information decoder (101).
    Type: Grant
    Filed: January 29, 2010
    Date of Patent: June 25, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Mamoru Sawahashi
  • Patent number: 8472363
    Abstract: A disclosed OFDM-based transmission device includes a unicast channel generating unit configured to generate a unicast channel; an MBMS channel generating unit configured to generate an MBMS channel; a multiplexing unit configured to time-division-multiplex the unicast channel and the MBMS channel in the same frequency band; and a transmitting unit configured to transmit time-division-multiplexed transmission symbols. In the disclosed transmission device, the guard interval length for the MBMS channel is set longer than the guard interval length for the unicast channel.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: June 25, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8472385
    Abstract: A base station, for transmitting common information and control information, includes a common information generating unit that generates the control information and the common information, a lower-layer control information generating unit that generates first lower-layer control information indicating a radio resource where the control information is to be placed and second lower-layer control information indicating a radio resource where the common information is to be placed.
    Type: Grant
    Filed: April 22, 2009
    Date of Patent: June 25, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8472394
    Abstract: A base station includes: means configured to manage frequency blocks; means configured to determine, for each frequency block, scheduling information for assigning one or more resource blocks to a communication terminal being in a good channel state; means configured to generate a control channel including the scheduling information for each frequency block; and means configured to frequency multiplexing control channels within the system frequency band and to transmit it. In addition, the base station transmits the control channel by separating a non-specific control channel to be decoded by a non-specific communication terminal and a specific control channel to be decoded by a communication terminal to which one or more resource blocks are assigned.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: June 25, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Mamoru Sawahashi, Nobuhiko Miki, Yoshihisa Kiskiyama
  • Patent number: 8462714
    Abstract: A base station communicating using multiple antennas includes a direction-of-arrival (DOA) estimation unit configured to estimate a direction of arrival based on a signal from a mobile station and to output direction-of-arrival information regarding the estimated direction of arrival; a DOA information multiplexing unit configured to multiplex the direction-of-arrival information from the direction-of-arrival estimation unit with a shared data channel to be transmitted to the mobile station; and an antenna weight multiplying unit configured to multiply a signal to be transmitted to the mobile station and including the shared data channel multiplexed with the direction-of-arrival information by antenna weights obtained based on the direction-of-arrival information from the direction-of-arrival estimation unit.
    Type: Grant
    Filed: September 29, 2008
    Date of Patent: June 11, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Mamoru Sawahashi