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: 8873501
    Abstract: A base station used in a mobile communication system employing a single carrier scheme for uplink transmission is disclosed. The base station includes a scheduler configured to allocate one or more uplink resource blocks to a user device according to uplink channel conditions of the user device; and a reporting unit configured to report scheduling information indicating the allocation result to the user device. An uplink control channel of the user device is mapped to a resource block in a transmission frame including multiple resource blocks according to a hopping pattern based on the scheduling information; and the uplink control channel is mapped to a resource block according to the same hopping pattern regardless of whether the uplink control channel is associated with a user data channel.
    Type: Grant
    Filed: June 13, 2007
    Date of Patent: October 28, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8873499
    Abstract: A user apparatus generates an uplink control channel including at least one of acknowledgement information and channel condition information on an downlink, and transmits the uplink control channel in a predefined dedicated band if no resource is assigned to transmit an uplink data channel. The uplink control channel includes multiple unit block sequences resulting from multiplication of the same factor with all chips of a CAZAC code sequence for the user apparatus.
    Type: Grant
    Filed: August 30, 2013
    Date of Patent: October 28, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8868122
    Abstract: A user apparatus to which radio access schemes that are a single-carrier scheme and a multicarrier scheme are applied, includes: a radio access scheme setting unit configured to set a radio access scheme; a discrete Fourier transform unit configured to perform discrete Fourier transform on a modulated symbol sequence when the set radio access scheme is the single-carrier scheme; a serial parallel conversion unit configured to perform serial parallel conversion on a modulated symbol sequence when the set radio access scheme is the multicarrier scheme; a frequency domain signal generation unit configured to assign a radio resource to the modulated symbol sequence on which discrete Fourier transform has been performed or to the modulated symbol sequence on which serial parallel conversion has been performed to generate a frequency domain signal; a transmission signal generation unit configured to perform inverse fast Fourier transform on the frequency domain signal to generate a transmission signal; a transmissi
    Type: Grant
    Filed: August 7, 2009
    Date of Patent: October 21, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Teruo Kawamura, Nobuhiko Miki, Mamoru Sawahashi
  • Patent number: 8861630
    Abstract: The present invention provides a reception apparatus and reception method that reduce the amount of operation processing, reduce the processing delay and allow high signal separation performance. The reception method of the present invention is characterized by receiving signals including a plurality of codewords transmitted by a plurality of streams and performing maximum likelihood detection-based signal separation in the same codeword in the received signals while performing continuous interference canceller-based signal separation between different codewords.
    Type: Grant
    Filed: October 21, 2010
    Date of Patent: October 14, 2014
    Assignee: NTT DoCoMo
    Inventors: Hidekazu Taoka, Mamoru Sawahashi
  • Patent number: 8843171
    Abstract: To provide a transmission power control method, base station apparatus and mobile station apparatus for enabling the transmission power in the mobile station apparatus having a plurality of antennas to be properly controlled, enabled is one of a common control mode for transmitting a common TPC command to perform transmission power control common to antennas (102a, 102b) to the mobile station apparatus (100) and an individual control mode for transmitting individual TPC commands to perform transmission power control individually on the antennas (102a, 102b) to the mobile station apparatus (100).
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: September 23, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Daisuke Nishikawa, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8817753
    Abstract: To provide a mobile terminal apparatus and radio communication method for enabling feedback control information to be efficiently transmitted on uplink channels, a radio communication method of the invention is characterized by having in a mobile terminal apparatus the steps of receiving a signal for each of a plurality of component carriers from a radio base station apparatus, generating feedback control information for each component carrier from the signal, mapping the feedback control information for each component carrier to suitable radio resources based on the number of component carriers, the presence or absence of uplink transmission data, and the number of bits of control information to transmit as feedback, and transmitting an uplink transmission signal mapped to the radio resources.
    Type: Grant
    Filed: April 20, 2010
    Date of Patent: August 26, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8811506
    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: Grant
    Filed: February 14, 2013
    Date of Patent: August 19, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Nobuhiko Miki, Mamoru Sawahashi
  • Publication number: 20140226515
    Abstract: A mobile communications system having a first base station and one or more second base stations is disclosed, wherein the first base station includes a first generator which generates a first known signal for use in common between the first base station and the second base station and a second known signal use specific to each of the first base station and the second base station, and a radio transmitter which wirelessly transmits, to a subordinate terminal apparatus, the first known signal and the second known signal which are generated by the first generator.
    Type: Application
    Filed: April 18, 2014
    Publication date: August 14, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8797946
    Abstract: A disclosed user device generates an uplink control channel including at least one of acknowledgement information and a channel quality indicator regarding downlink and transmits the uplink control channel via a dedicated frequency band when no resource is allocated for transmission of an uplink data channel. The uplink control channel includes multiple unit blocks constituting a subframe and each of the unit blocks includes a sequence generated by multiplying all chips of an orthogonal code sequence assigned to the user device by the same factor.
    Type: Grant
    Filed: March 13, 2008
    Date of Patent: August 5, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8780850
    Abstract: A user equipment terminal for transmitting an uplink control channel to a base station according to a single carrier scheme includes a reception determining unit configured to determine reception of data, which are transmitted from the base station according to scheduling, and generate a reception determination result as first control information; and a control information multiplexing unit configured to assign the first control information to a first radio resource positioned at an end of a system band and assign second control information, which is transmitted with a radio resource dedicated to the user equipment terminal, to a predetermined position in a second radio resource adjacent to the first radio resource, to multiplex the first control information and the second control information into the uplink control channel. The present invention also relates to a base station and an uplink control channel configuration method.
    Type: Grant
    Filed: October 19, 2012
    Date of Patent: July 15, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8743714
    Abstract: A mobile communications system having a first base station and one or more second base stations is disclosed, wherein the first base station includes a first generator which generates a first known signal for use in common between the first base station and the second base station and a second known signal use specific to each of the first base station and the second base station, and a radio transmitter which wirelessly transmits, to a subordinate terminal apparatus, the first known signal and the second known signal which are generated by the first generator.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: June 3, 2014
    Assignee: NTT Docomo, Inc.
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8737380
    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: May 27, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Motohiro Tanno, Kenichi Higuchi, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 8737283
    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: February 8, 2013
    Date of Patent: May 27, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Patent number: 8725186
    Abstract: The present invention provides a base station apparatus capable of preventing degrading of throughput performance even when feedback information amount on precoding in uplink MIMO transmission is reduced. This base station (200) has a scheduler (231) for determining resource blocks used in wireless communications with each mobile station (100) adaptively, a precoding weight selecting section (232) for selecting a precoding weight for controlling phase and/or amplitude of a transmission signal for each antenna in the mobile station (100) based on reception quality on uplink at the resource blocks determined to the mobile station (100); and transmission/reception sections (206a and 206b) for transmitting the determined precoding weight to the mobile station (100).
    Type: Grant
    Filed: September 18, 2009
    Date of Patent: May 13, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Yuichi Kakishima, Hiroyuki Kawai, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8711815
    Abstract: To provide a mobile terminal apparatus, radio base station apparatus and radio communication method capable of supporting user multiplexing methods for enabling more users to be efficiently multiplexed on an uplink shared channel, the mobile terminal apparatus performs spreading processing for multiplying a data signal by a code varying for each user, and transmits the spreading-processed data signal to the radio base station apparatus on the uplink shared channel, and the radio base station apparatus receives the data signal, and user-separates a reception signal in which is mixed a plurality of users multiplied by spreading codes varying for each user into desired user signals to be data signals for each user.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: April 29, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Mamoru Sawahashi
  • Patent number: 8711770
    Abstract: A base station apparatus used in a mobile communication system to which an OFDM scheme is applied in downlink is provided with: a scheduler configured to perform assignment of radio resources to a user apparatus for each subframe; a control channel generation unit configured to generate a control channel for reporting a result of scheduling by the scheduler to the user apparatus; and a mapping unit configured to map the control channel and a data channel, wherein the control information includes information indicating a radio resource amount used for the control channel, and the mapping unit multiplexes information indicating the radio resource amount used for the control channel into a first OFDM symbol.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: April 29, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8699443
    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: Grant
    Filed: March 8, 2013
    Date of Patent: April 15, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8700025
    Abstract: A mobile communications system includes a radio base station and a remote radio apparatus connected with a high-speed transmission medium to the radio base station. A user apparatus includes a unit which measures a received level of a signal transmitted from the radio base station and a received level of a signal transmitted from the remote radio apparatus and detects a change in relative magnitudes of measured values; a unit which measures a path loss between the user apparatus and the radio base station and a path loss between the user apparatus and the remote radio apparatus and detects a change in relative magnitudes of measured values; and a transmitter which transmits a report signal which shows that a predetermined event has occurred. The predetermined event occurs if the relative magnitudes of the received levels are reversed and/or if the relative magnitudes of the path losses are reversed.
    Type: Grant
    Filed: July 27, 2009
    Date of Patent: April 15, 2014
    Assignee: NTT Docomo, Inc.
    Inventors: Akihito Morimoto, Motohiro Tanno, Yoshihisa Kishiyama, Mamoru Sawahashi
  • Publication number: 20140098800
    Abstract: A mobile station, a base station, a mobile communication system and a communication method enabling operations associated with simultaneous uplink reception in multiple stations to be simplified are provided. The base station includes a transmission timing determining unit determining a transmission timing based on scheduling conducted upon a data transmission request from a mobile station and notifying the mobile station of the transmission timing, and a receiving unit receiving data in accordance with the transmission timing.
    Type: Application
    Filed: December 13, 2013
    Publication date: April 10, 2014
    Applicant: NEC CORPORATION
    Inventors: Akihito MORIMOTO, Kenichi HIGUCHI, Motohiro TANNO, Mamoru SAWAHASHI, Toshifumi SATO
  • Patent number: 8693428
    Abstract: A base station determines both a transmission interval between scheduling requests which a mobile station transmits before transmitting uplink data and information about radio resources used for transmitting the scheduling requests, based on the status of the mobile station and/or QoS information transmitted from the mobile station. The mobile station generates the scheduling requests. The mobile station controls the transmission of the scheduling requests based on the transmission interval and the radio resources. The mobile station transmits the scheduling requests. The base station detects correlation based on the scheduling requests which are transmitted from the mobile station based on the transmission interval and the radio resources, and feeds delay information back to the mobile station. The mobile station maintains synchronization based on the delay information transmitted from the base station.
    Type: Grant
    Filed: June 13, 2007
    Date of Patent: April 8, 2014
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi