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: 8462711
    Abstract: A base station apparatus in a mobile communications system which uses orthogonal frequency division multiplexing (OFDM) for downlink is disclosed. The base station includes a unit which generates a first signal; a unit which generates a second signal; a unit which multiplexes the first signal and the second signal to map the multiplexed signals to a sub-carrier to generate a transmit symbol; and a mapping determining unit which determines a position of mapping the second signal to the sub-carrier, wherein the mapping determining unit determines the mapping position based on a cell ID or cell group ID, and a mapping pattern defined with a sequence having two-stage structure.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: June 11, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hiroyuki Ishii, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8463203
    Abstract: A base station apparatus in a radio communication system where transmit diversity is applied in uplinks includes a reference signal measurement unit configured to measure a receive level of the reference signal, a switch pitch determination unit configured to determine the antenna switch pitch of transmitting the reference signal based on the receive level measured by the reference signal measurement unit, and a transmitting unit configured to transmit the antenna switch pitch determined by the switch pitch determination unit.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: June 11, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Mamoru Sawahashi
  • Publication number: 20130142101
    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: Application
    Filed: January 15, 2013
    Publication date: June 6, 2013
    Inventors: Motohiro Tanno, Kenichi Higuchi, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 8457055
    Abstract: A disclosed radio base station is used in a mobile communication system employing a single carrier scheme for uplink and includes a scheduler configured to allocate radio resources such that a first control channel accompanying an uplink data channel is transmitted using the same frequency band allocated to the uplink data channel and a second control channel, which is to be transmitted regardless of presence or absence of the uplink data channel, is transmitted using a dedicated frequency band reserved for the second control channel if no frequency band is allocated to the uplink data channel; and a reporting unit configured to report scheduling information indicating the allocation results to a user device. The scheduler is configured not to allocate the radio resources to the uplink data channel of the user device in a unit transmission period reserved for transmission of the second control channel of the user device.
    Type: Grant
    Filed: August 13, 2007
    Date of Patent: June 4, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8451792
    Abstract: The object is achieved by providing a base station apparatus for performing time and frequency scheduling in uplink packet access with: an interference amount measurement part configured to measure an uplink interference amount for each interference amount measurement unit which comprises a predetermined period and a predetermined number of frequency blocks; an interference amount determination part configured to determine whether the uplink interference amount satisfies a predetermined condition; and an overload indicator reporting part configured to report an overload indicator to a neighboring cell when the predetermined condition is satisfied.
    Type: Grant
    Filed: April 25, 2008
    Date of Patent: May 28, 2013
    Assignee: NEC Corporation
    Inventors: Motohiro Tanno, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi, Toshifumi Sato
  • Publication number: 20130128998
    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: Application
    Filed: January 15, 2013
    Publication date: May 23, 2013
    Inventors: Motohiro Tanno, Kenichi Higuchi, Mamoru Sawahashi, Yoshihisa Kishiyama
  • Patent number: 8442220
    Abstract: A base station generates a unicast channel, a MBMS channel, and a pilot channel, that are multiplied by a scrambling code specific to a particular cell. The pilot channel is replicated as necessary. The unicast channel and the MBMS channel are time-multiplexed. For data in a unit transmission frame, a same frequency component is multiplied by a same scrambling code.
    Type: Grant
    Filed: February 7, 2007
    Date of Patent: May 14, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8437294
    Abstract: A mobile station includes a channel quality estimation unit configured to estimate downlink channel quality based on a reference signal from a base station and to output the estimated downlink channel quality as channel estimation information; an acknowledgement information determining unit configured to determine whether a downlink data channel from the base station is correctly received and to output the determination result as acknowledgement information; and an acknowledgement information prioritizing unit configured to cause the acknowledgement information to be preferentially transmitted to the base station if transmission timings of the channel estimation information and the acknowledgement information coincide.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: May 7, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8433328
    Abstract: A base station apparatus is disclosed which communicates with a user apparatus which transmits an uplink signal using a single-carrier scheme. The base station includes a sequence-identifier determining unit which performs scheduling to allocate a frequency based on an uplink channel reception state of the user apparatus, and which determines a second sequence identifier for use by the user apparatus based on a first sequence identifier in a length of a reference signal sequence for transmitting in a maximum bandwidth in which the user apparatus can transmit, and a frequency bandwidth allocated to the user apparatus.
    Type: Grant
    Filed: June 17, 2008
    Date of Patent: April 30, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Teruo Kawamura, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8428641
    Abstract: A transmission power control is disclosed, where the transmission power control includes transferring, from a second radio base station to a first radio base station, a second uplink signal received from a mobile station in a second cell, synthesizing, at the first radio base station, a first uplink signal received from the mobile station in a first cell with the second uplink signal transferred from the second radio base station, and generating and transmitting a transmission power control signal for controlling a transmission power of an uplink signal at the mobile station based on a reception quality of an uplink signal obtained by synthesizing the first uplink signal with the second uplink signal.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: April 23, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Akihito Morimoto, Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8428019
    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: August 13, 2008
    Date of Patent: April 23, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8428652
    Abstract: A disclosed user apparatus includes a random access channel generating unit configured to generate a random access channel; a control channel generating unit configured to generate a control channel in accordance with scheduling information received from a base station; and an uplink transmission signal generating unit configure to generate an uplink transmission signal including the random access channel or the control channel. Further, the purpose ID indicating at least whether there is a user ID uniquely allocated by the base station is included in the random access channel or the control channel.
    Type: Grant
    Filed: June 1, 2011
    Date of Patent: April 23, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8428043
    Abstract: A base station for communicating within a system band including plural basic frequency blocks includes a signal generating unit configured to generate data and control signals; an intermediate signal generating unit configured to generate intermediate signals; a multiplexing unit configured to add one or more subcarriers such that center frequencies of signal bands for the respective basic frequency blocks are placed at predetermined frequency intervals, and multiplex the intermediate signals and data and control signals; and a transmitting unit configured to transmit the multiplexed signals.
    Type: Grant
    Filed: August 11, 2009
    Date of Patent: April 23, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Motohiro Tanno, Mamoru Sawahashi
  • Patent number: 8422355
    Abstract: A base station apparatus for use in a mobile communication system includes: a unit configured to generate a reference signal; a unit configured to generate a transmission symbol including the reference signal; a unit configured to transmit the transmission symbol for each sector; and a unit configured to monitor a radio propagation state. The reference signal is generated by multiplying a first sequence formed by a non-orthogonal code sequence which is different at least between an adjacent cell and an own cell, by a second sequence. Whether to form the second sequence by using an orthogonal code sequence which is different among sectors or by using a non-orthogonal code sequence is determined according to the radio propagation state.
    Type: Grant
    Filed: May 21, 2008
    Date of Patent: April 16, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8422574
    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: June 16, 2008
    Date of Patent: April 16, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Nobuhiko Miki, Mamoru Sawahashi
  • Patent number: 8422356
    Abstract: A base station used in a mobile communications system which uses orthogonal frequency division multiplexing (OFDM) for downlink is disclosed. The base station includes: a unit which provides a reference signal; a unit which multiplexes a control signal and the reference signal, and generates a transmit symbol; and a unit which inverse Fourier transforms the transmit symbol and wirelessly transmits the transformed transmit symbol, wherein a first sequence including a random code sequence and a second sequence belonging to an orthogonal-code sequence group are multiplied with the reference signal, mutually different ones of the orthogonal code sequences are used in the respective multiple sectors belonging to the same cell, and different ones of the random code sequences are used in the respective two or more cells.
    Type: Grant
    Filed: October 30, 2007
    Date of Patent: April 16, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8416872
    Abstract: The radio communication apparatus includes two or more antennas, a receiving unit for receiving a notice signal from a communication partner, two or more units for changing the number of data sequences and for coupling to the antennas according to two or more transmitting methods out of a MIMO multiplexing method, a MIMO diversity method, and an adaptive array antenna method, a selecting unit for selecting at least one out of the two or more units based on the notice signal, and a transmitting unit for notifying the communication partner of the transmission method corresponding to the selected unit.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: April 9, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Kenichi Higuchi, Noriyuki Maeda, Mamoru Sawahashi
  • Patent number: 8411634
    Abstract: A user apparatus transmits an uplink control signal to a base station apparatus using a single carrier scheme. The user apparatus includes: a unit configured to receive a downlink control signal and a downlink data signal; a unit configured to prepare acknowledgement information indicating positive acknowledgement or negative acknowledgement for the downlink data signal; a unit configured to prepare the uplink control signal including the acknowledgement information; a unit configured to transmit the uplink control signal using different resources which are different from resources that can be used for an uplink data signal; and a storage unit configured to store predetermined correspondence relationship which uniquely associates resources of the downlink control signal or the downlink data signal with resources used for the uplink control signal.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: April 2, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Nobuhiko Miki, Kenichi Higuchi, Mamoru Sawahashi
  • Patent number: 8406184
    Abstract: A user apparatus in a mobile communications system is disclosed. The user apparatus includes a unit which receives, from a base station apparatus, a downlink control signal including information for allocating a radio resource; a unit which determines, depending on a channel status, a pre-encoding matrix indicator (PMI) which indicates a pre-encoding matrix to be applied to multiple antennas of the base station apparatus; and a unit which transmits, to the base station apparatus, an uplink signal including the PMI, wherein, if the radio resource is allocated to a physical uplink shared channel of the user apparatus, the PMI is transmitted using a part of the radio resource, and, wherein, if the radio resource is not allocated to the physical uplink shared channel of the user apparatus, the PMI is transmitted in a physical uplink control channel which is allocated, in a fixed manner, to the user apparatus.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: March 26, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidekazu Taoka, Mamoru Sawahashi, Nobuhiko Miki
  • Patent number: 8400975
    Abstract: A user apparatus to be used in a mobile communications system including multiple cells is disclosed. The user apparatus includes a unit which receives a sync channel; a unit which extracts a primary sync channel and a secondary sync channel from the sync channel and conducts a cell search; and a unit which controls, based on a condition for setting an averaging time in a time direction in the cell search, a correlation detection time in a correlation detection performed in the unit which conducts the cell search.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: March 19, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Satoshi Nagata, Kenichi Higuchi, Mamoru Sawahashi