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: 9008060
    Abstract: A mobile terminal apparatus, a radio base station apparatus and a radio communication method are provided which can perform optimum control during downlink CoMP transmission in an LTE-A system.
    Type: Grant
    Filed: January 5, 2011
    Date of Patent: April 14, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Akihito Morimoto, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 9008034
    Abstract: A disclosed base station transmits a broadcast channel to a user device a predefined number of times in a predetermined cycle for communication with the user device. The base station includes a repetition unit configured to repeat the broadcast channel, after the broadcast channel is channel-coded, for the predefined number of times to generate multiple broadcast channels; and a signal waveform changing unit configured to process the generated broadcast channels such that the processed broadcast channels have different signal waveforms. Positions of the broadcast channels in the order of transmission in the predetermined cycle are associated with the signal waveforms of the broadcast channels.
    Type: Grant
    Filed: July 20, 2012
    Date of Patent: April 14, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Motohiro Tanno, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 9001638
    Abstract: To enable an uplink control signal subjected to user multiplexing by an orthogonally multiplexing method using the cyclic shift to be user-demultiplexed, and further enable channel estimation accuracy to be improved, a radio communication method of the invention is characterized in that a mobile terminal apparatus provides a plurality of subcarriers with phase rotation amounts set to minimize the number of unit subcarriers for coherent averaging in association with the number of multiplexed users, and transmits an uplink control signal using the plurality of subcarriers provided with the phase rotation amounts, and that a radio base station apparatus receives the uplink control signal, performs coherent averaging on reference signal using the different number of unit subcarriers corresponding to the number of multiplexed users to demultiplex into a reference signal for each of the users, and estimates a channel variation using the demultiplexed reference signal.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: April 7, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Publication number: 20150085819
    Abstract: To provide a radio base station apparatus and radio communication method capable of performing radio communications using downlink reference signal structures suitable for antenna virtualization, a radio base station apparatus (200) has a plurality of transmission antennas, generates CRSs used in demodulation of at least downlink control information, CQI-RSs generated for each of the transmission antennas used in measurement of channel quality, and DM-RSs generated for each stream used in demodulation of downlink transmission data, and multiplexes the CRSs, CQI-RSs and DM-RSs into a same transmission time unit to transmit from each of the antennas.
    Type: Application
    Filed: October 16, 2014
    Publication date: March 26, 2015
    Inventors: Yoshihisa Kishiyama, Hidekazu Taoka, Mamoru Sawahashi
  • Patent number: 8976723
    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: August 19, 2013
    Date of Patent: March 10, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Kenichi Higuchi, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Publication number: 20150063292
    Abstract: A transmission apparatus is provided with radio resource assignment means that assigns radio resources to each physical channel according to a type of the physical channel; and transmission means that transmits information to be transmitted by each physical channel using the assigned radio resources.
    Type: Application
    Filed: October 15, 2014
    Publication date: March 5, 2015
    Applicant: NTT DOCOMO, INC.
    Inventors: Nobuhiko Miki, Motohiro Tanno, Kenichi Higuchi, Mamoru Sawahashi, Hiroyuki Atarashi
  • Patent number: 8971897
    Abstract: A centralized-control base station connected to a first transceiving unit and a second transceiving unit includes a first signal quality obtaining unit configured to obtain both uplink signal quality from a mobile station to the first transceiving unit and downlink signal quality from the first transceiving unit to the mobile station; a second signal quality obtaining unit configured to obtain both uplink signal quality from the mobile station to the second transceiving unit and downlink signal quality from the second transceiving unit to the mobile station; and a control unit configured to allow downlink data to be transmitted from the first transceiving unit, downlink feedback information to be received by the second transceiving unit, uplink data to be received by the second transceiving unit, and uplink feedback information to be transmitted from the first transceiving unit, when the downlink signal quality from the first transceiving unit to the mobile station is better than the downlink signal quality f
    Type: Grant
    Filed: June 22, 2009
    Date of Patent: March 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Motohiro Tanno, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 8971283
    Abstract: A radio resource assignment method for a physical channel in an uplink directed from a mobile apparatus to a base station in a radio communication system, includes: assigning a contention-based channel and a scheduled channel according to one of a time division scheme, a frequency division scheme, and a hybrid scheme of the time division scheme and the frequency division scheme. In addition, radio resources are properly assigned to each of the contention-based channel, a common control channel of the scheduled channel, and a shared data channel of the scheduled channel.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: March 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Kenichi Higuchi, Hiroyuki Atarashi, Mamoru Sawahashi
  • Patent number: 8971286
    Abstract: A mobile terminal apparatus and radio base station apparatus supporting each of a plurality of mobile communication systems when the plurality of mobile communication systems coexists, where the mobile terminal apparatus performs a cell search using an SCH signal included in one downlink CC among a plurality of downlink CCs, and where the radio base station apparatus broadcasts a DBCH signal including information of an uplink CC paired with an initial downlink CC including the SCH signal obtained by the cell search, and transmits a response signal of an RACH signal from the mobile terminal apparatus to the mobile terminal apparatus in the initial downlink CC, and where the mobile terminal apparatus transmits a shared channel signal including information of a transmission/reception bandwidth of the mobile terminal apparatus to the radio base station apparatus in the uplink CC, and where the radio base station apparatus transmits a control signal including assignment information of a downlink CC and an uplink C
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: March 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8971902
    Abstract: A mobile communication system includes a first assignment unit configured to assign radio resources to a user in a W-CDMA system, a second assignment unit configured to assign radio resources to a user in a LTE system, a dual mode terminal capable of communicating in the W-CDMA system and the LTE system, and a selection unit configured to select the first assignment unit or the second assignment unit depending on a type of user traffic data in communication with the dual mode terminal. The assignment unit selected by the selection unit determines which of the radio resources is available for the dual mode terminal and signals the determined radio resources to the dual mode terminal.
    Type: Grant
    Filed: October 31, 2008
    Date of Patent: March 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Nobuhiko Miki, Mamoru Sawahashi, Kenichi Higuchi
  • Patent number: 8964607
    Abstract: A communication apparatus to be used for a newer system employing an FDD scheme in an area where an older system and the newer system coexist. The communication apparatus includes a first communication unit communicating at least a downlink data channel of the newer system using a frequency band belonging to a first frequency range (3.4-3.8 GHz); and a second communication unit communicating at least an uplink control channel of the newer system using a frequency band belonging to a second frequency range (2 GHz band) lower than the first frequency range. The second frequency range is used for uplink and downlink communications in the older system.
    Type: Grant
    Filed: April 30, 2009
    Date of Patent: February 24, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Motohiro Tanno, Mamoru Sawahashi, Seizo Onoe, Nobuhiko Miki, Yoshihisa Kishiyama, Hidekazu Taoka
  • Patent number: 8964671
    Abstract: A base station apparatus in a mobile communications system has a unit which transmits, to one or more user apparatuses, a downlink control signal including information for allocating a radio resource, a unit which receives an uplink signal from the one or more user apparatuses, and a unit which determines, based on a feedback from the user apparatus, a pre-encoding matrix indicator (PMI) indicating a pre-encoding matrix to be applied to multiple antennas of the base station apparatus. When a number of multiplexed users in the downlink control signal is no less than a predetermined number, the PMI indicating the pre-encoding matrix to be applied to a whole system bandwidth of the mobile communications system is reported to each of the user apparatuses.
    Type: Grant
    Filed: June 18, 2012
    Date of Patent: February 24, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Hidekazu Taoka, Mamoru Sawahashi, Nobuhiko Miki
  • Patent number: 8958374
    Abstract: A base station for transmitting common information which is used in common by plural mobile stations includes a common information generating unit configured to generate the common information; a lower-layer control information generating unit configured to generate lower-layer control information indicating a radio resource where the common information is to be placed; a multiplexing unit configured to multiplex the lower-layer control information and the common information into one or more frequency blocks among a plurality of frequency blocks included within a system bandwidth, the system bandwidth being divided into the plurality of frequency blocks each corresponding to a minimum value of maximum transmission and reception bandwidths used by the plural mobile stations; and a transmitting unit configured to transmit the multiplexed lower-layer control information and common information.
    Type: Grant
    Filed: April 23, 2009
    Date of Patent: February 17, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8948159
    Abstract: A transmitter includes an amplitude adjustment unit multiplying an amplitude adjustment sequence value for adjusting amplitude with a synchronization channel transmitted from a base station for establishing synchronization with a mobile station.
    Type: Grant
    Filed: January 15, 2013
    Date of Patent: February 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Motohiro Tanno, Kenichi Higuchi, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 8923878
    Abstract: A mobile station, where the mobile station includes a reception quality measurement unit, a channel quality information transmission unit, and a control signal transmission unit, where the reception quality measurement unit is configured to measure a reception quality of a pilot signal of each of a plurality of cells, when a radio link is established with the plurality of cells, where the channel quality information transmission unit is configured to transmit, to a first cell having the beset reception quality among the plurality of cells, channel quality information corresponding to the reception quality, and where the control signal transmission unit is configured to transmit, to a cell other than the first cell among the plurality of cells, a control signal requesting not to transmit a data signal by using the same resource as the first cell.
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: December 30, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Akihito Morimoto, Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Publication number: 20140378139
    Abstract: To provide a radio base station apparatus and mobile terminal for enabling cell selection to be performed in a faster cell switching period in handover, the radio base station apparatus of the invention has a plurality of transmission/reception sections capable of being extended to remote sites, an FCS application determining section that determines whether to apply fast cell selection in handover based on information from the mobile terminal, and a multi-cell scheduling control section that controls transmission/non-transmission of the first and second transmission/reception sections when the FCS application determining section determines that FCS is applied.
    Type: Application
    Filed: September 9, 2014
    Publication date: December 25, 2014
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8897281
    Abstract: Provided is a radio base station apparatus capable of transmitting a control signal efficiently even in radio communications using a system band that includes a plurality of component carriers. In the radio base station apparatus, control signals of transport blocks corresponding to the plural component carriers are coded jointly and the coded control signal is assigned to one or plural component carriers to be transmitted. A mobile terminal apparatus receives data from the radio base station apparatus, separates the control signal from the received data and decodes the separated control signal thereby to obtain control information of the transport blocks of the corresponding component carriers.
    Type: Grant
    Filed: January 29, 2010
    Date of Patent: November 25, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Yoshihisa Kishiyama, Satoshi Nagata, Mamoru Sawahashi
  • Patent number: 8897231
    Abstract: A disclosed mobile station includes a multiplexing portion that multiplexes a contention-based channel and a non-contention-base channel, and a transmitting portion that transmits the multiplexed contention-based and non-contention-based channels to a base station. In the mobile station, the contention-based channel and the non-contention-based channel are distinguished from whether scheduling is performed before transmission in the base station. The contention-based channel includes one or more of a fast access channel, a reservation channel, and a synchronization channel. The non-contention-based channel includes one or more of an uplink shared data channel and an uplink shared control channel. The fast access channel includes traffic data, or control data having a data size smaller than a predetermined size, or a combination thereof. The reservation channel includes information to request scheduling the non-contention-based channel.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: November 25, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Mamoru Sawahashi, Kenichi Higuchi
  • Patent number: 8880089
    Abstract: In a mobile communication system including a first base station and a second base station, the first base station includes: a user information obtaining unit configured to obtain user information in the first base station, and the second base station includes: a user information obtaining unit configured to obtain user information in the second base station; a base station internal information collection unit configured to collect user information in the first and the second base stations; and a resource assignment determination unit configured to determine radio resources that can be used by the first base station and radio resources that can be used by the second base station based on the user information in the first and the second base stations.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: November 4, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Akihito Morimoto, Motohiro Tanno, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8873437
    Abstract: A base station apparatus in a mobile communication system allowing for user equipment terminals having different numbers of receiving antennas is disclosed. The base station apparatus includes a mapping unit mapping a reference signal, a primary broadcasting signal, a synchronization signal, and an L1/L2 control signal onto a predetermined signal format; and a transmission unit transmitting the mapped signals, in which, within a sub-frame, the mapping unit maps the L1/L2 control signal and the primary broadcasting signal so as to be time-domain multiplexed, maps the primary broadcasting signal and the synchronization signal within a predetermined bandwidth in a middle of a system bandwidth, maps a reference signal included in a predetermined transmission stream within the predetermined bandwidth, but does not map a reference signal included in a transmission stream other than the predetermined transmission stream within the predetermined bandwidth.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: October 28, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi