Patents by Inventor Tetsushi Abe

Tetsushi Abe 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: 9179349
    Abstract: The present invention provides a mobile terminal apparatus, a base station apparatus, and a communication control method, which allow control suitable for interference reduction in a layered network such as HetNet, and which support a next-generation mobile communication system. A mobile terminal apparatus has a receiving section (103) that receives radio frames of a pico cell, in which a protected subframe, the transmission of which by a macro cell is suppressed, and a non-protected subframe, the transmission of which by the macro cell is not suppressed, coexist, a measurement section (112) that measures reception quality from the reference signals multiplexed individually on the protected subframe and the non-protected subframe, and a transmission section (103) that notifies two types of reception quality information of the protected subframe and the non-protected subframe, measured in the measurement section (112), to a base station apparatus (20B).
    Type: Grant
    Filed: November 7, 2011
    Date of Patent: November 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe, Yusuke Ohwatari, Nobuhiko Miki
  • Patent number: 9179466
    Abstract: To provide a base station apparatus, mobile terminal apparatus and communication control method for enabling control adapted to interference inside a Heterogeneous network to be performed to support the next-generation mobile communication system, a base station apparatus (20) shares at least a part of the frequency band with another base station apparatus (40) that covers a macro-cell, covers a pico-cell (C1), is capable of transmitting a downlink transmission frame at transmission timing different from the another base station apparatus (40), and is configured to set resources, in which the downlink transmission frame undergoes interference from another downlink transmission frame including a blank period transmitted from the another base station apparatus (40), as blank resources, and assign user data to the downlink transmission frame while avoiding the blank resources.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: November 3, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Tetsushi Abe, Satoshi Nagata, Nobuhiko Miki, Sangiamwong Jaturong
  • Patent number: 9173123
    Abstract: The present invention provides a base station apparatus, a mobile terminal apparatus and a communication control method which can improve the accuracy of channel quality estimation. A communication control method includes the steps of: arranging a CSI-RS, which is a reference signal for downlink channel estimation, in resources of subframes for CSI-RS transmission; setting, in the subframes for CSI-RS transmission, resources to which the CSI-RS is allocated in neighboring areas, to be muting resources; and reporting transmission interval information, which indicates a transmission interval of subframes that are set at the same timing in a transmission cycle of a subframe for CSI-RS transmission in a subject area and in a transmission cycle of a subframe for CSI-RS transmission in the neighboring areas, to a mobile terminal apparatus.
    Type: Grant
    Filed: October 3, 2011
    Date of Patent: October 27, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Nobuhiko Miki, Tetsushi Abe, Yusuke Ohwatari, Satoshi Nagata
  • Patent number: 9167448
    Abstract: The present invention provides a mobile terminal apparatus, a base station apparatus, and a communication control method, which allow control suitable for interference reduction in a layered network such as HetNet, and which support a next-generation mobile communication system.
    Type: Grant
    Filed: November 7, 2011
    Date of Patent: October 20, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe, Yusuke Ohwatari, Nobuhiko Miki
  • Patent number: 9124320
    Abstract: A mobile terminal apparatus estimates downlink channel states using respective reference signals included in downlink signals from plural cells; selects PMIs (Precoding Matrix Indicators) using a codebook based on the channel states; estimates a phase difference between the cells based on the selected PMIs or the channel states; and transmits information of the phase difference and the selected PMIs to radio base station apparatuses of the respective cells. A radio base station apparatus receives an uplink signal including a PMI and the information of the phase difference between the cells; multiplies a transmission signal by a precoding weight corresponding to the PMI; adjusts the phase difference between the cells with use of the information of the phase difference between the cells; and transmits the transmission signal to a radio base station apparatus of another cell by coordinated multi-point transmission.
    Type: Grant
    Filed: December 9, 2011
    Date of Patent: September 1, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe, Yoshihisa Kishiyama
  • Patent number: 9119104
    Abstract: Provided is a mobile communication method including a step A of transmitting, by a mobile station UE, “Measurement Report” including measurement results of radio qualities of neighboring cells #2 to #4 in a downlink to a radio base station eNB#1 that manages a cell #1 in which the mobile station UE is in communication, a step B of selecting, by the radio base station eNB#1, the cell #2 from among the neighboring cells #2 to #4 on the basis of the “Measurement Report”, and a step C of transmitting, by the radio base station eNB#1, “DL HI indication” indicating an influence of interference on the mobile station UE in a downlink direction being strong to a radio base station eNB#2 that manages the cell #2.
    Type: Grant
    Filed: November 11, 2011
    Date of Patent: August 25, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Hideaki Takahashi, Tetsushi Abe, Mikio Iwamura
  • Patent number: 9107111
    Abstract: In order to assure reception of broadcast information by a user terminal handed over to a micro base station by CRE (Cell Range Expansion) and to reduce the number of transmission stopped subframes in a macro base station, the present invention provides a notification method for a user terminal to receive modification notification information for notifying modification in system information from the micro base station, the notification method including: the macro base station notifying the micro base station of a subframe pattern including a protection subframe to protect the modification notification information every a plurality of radio frames; and the micro base station notifying the user terminal of identification information of the protection subframe in the subframe pattern.
    Type: Grant
    Filed: November 8, 2011
    Date of Patent: August 11, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Tetsushi Abe, Mikio Iwamura, Hideaki Takahashi, Hiroyuki Ishii, Satoshi Nagata, Naoto Ookubo, Nobuhiko Miki, Anil Umesh
  • Patent number: 9071404
    Abstract: To reduce interference that a user terminal connecting to a base station apparatus forming a large-scale cell undergoes from a base station apparatus forming a small-scale cell in a radio communication system in which the small-scale cell is provided in the large-scale cell, a femto-base station forming a femto-cell provided in a macro-cell receives cell identification information of a macro-base station, determines cell identification information of the femto-base station based on the received cell identification information of the macro-base station so as to reduce interference to a control format indicator channel assigned to radio resources by the macro-base station, and controls assignment of control channels to radio resources based on the determined cell identification information of the femto-base station.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: June 30, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Zubin Bharucha, Auer Gunther, Tetsushi Abe, Nobuhiko Miki
  • Patent number: 9055480
    Abstract: A mobile communication method according to the present invention includes a step A of notifying, by a radio base station eNB, a mobile station UE during communication in a subordinate cell #1 of “CSI-RS/Muting configuration information” indicating a transmission method of CSI-RS; and a step B of performing, by the mobile station UE, a reception process on the basis of the “CSI-RS/Muting configuration information”.
    Type: Grant
    Filed: November 18, 2011
    Date of Patent: June 9, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe, Naoto Ookubo, Mikio Iwamura
  • Publication number: 20150156772
    Abstract: A radio base station apparatus that reports SRS (Sounding Reference Signal) transmission control information to a mobile terminal apparatus and controls transmission of an SRS by the mobile terminal apparatus is described. The radio base station includes an SRS setting section configured to select bit information to report to the mobile terminal apparatus, from a table having bit information to indicate not to trigger the SRS and bit information to indicate to trigger the SRS using a default SRS parameter and a reporting section configured to report the bit information for the mobile terminal apparatus using a downlink control channel.
    Type: Application
    Filed: December 2, 2014
    Publication date: June 4, 2015
    Inventors: Daisuke Nishikawa, Kazuaki Takeda, Tetsushi Abe, Yoshihisa Kishiyama
  • Patent number: 9037076
    Abstract: To provide a radio relay station apparatus and radio relay method for enabling the radio relay station apparatus to identify a multi-hop relay signal and relay a downlink signal suitably, a first radio relay station apparatus or a radio base station apparatus generates a control signal indicative of passing through a radio relay station apparatus, and transmits the control signal in downlink, and a second radio relay station apparatus receives the control signal, demodulates a downlink signal based on the control signal, modulates the demodulated downlink signal, and transmits the modulated downlink signal.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: May 19, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe
  • Patent number: 9037171
    Abstract: To cancel interference from the other cells and improve throughput characteristics without needing complicated processing, provided are a reception section that receives a reception signal including signal components from a plurality of base station apparatuses (BSs), and a signal detection and channel estimation section (61) that performs signal detection and channel estimation processing based on a factor graph on the reception signal, where the signal detection and channel estimation section (61) estimates interfering components from base station apparatuses of the other cells except a desired base station apparatus included in the reception signal at a symbol level, and reuses the interfering components in the signal detection and channel estimation processing based on the factor graph.
    Type: Grant
    Filed: June 10, 2011
    Date of Patent: May 19, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Tetsushi Abe, Alexander Tyrrell, Auer Gunther
  • Patent number: 9036483
    Abstract: A mobile communication method according to the present invention includes a step of setting, by a radio base station eNB#10, when a subframe designated by a pattern of ABS, the pattern being notified by a radio base station eNB#1, matches a subframe set as an MBSFN subframe, the matching subframe as an MBSFN subframe used for “eICIC”.
    Type: Grant
    Filed: October 20, 2011
    Date of Patent: May 19, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Hideaki Takahashi, Tetsushi Abe
  • Patent number: 8995349
    Abstract: The present invention is designated to reduce the deterioration of transmission characteristics upon data transmission, even when soft buffer memory for retransmission control is not sufficiently secured in a mobile terminal apparatus. The present invention provides the steps of, in a base station apparatus (eNB), performing channel coding of information bits (ST 802), performing a rate matching process for the coded bits after interleaving (ST 804), and transmitting transmission data to match the coded bit length after rate matching, to a mobile terminal apparatus (UE) (ST 806), and, in the mobile terminal apparatus (UE), receiving the transmission data (ST 807), performing channel decoding of the received data (ST 810), and discarding part of the received data in accordance with the size of the soft buffer memory in the mobile terminal apparatus (UE) and storing this in the soft buffer memory (ST 812 and ST 813).
    Type: Grant
    Filed: January 5, 2012
    Date of Patent: March 31, 2015
    Assignee: NTT DOCOMO, INC.
    Inventors: Tetsushi Abe, Kazuaki Takeda, Naoto Ookubo, Hiroyuki Ishii, Yuta Sagae
  • Patent number: 8937929
    Abstract: Provided are a base station apparatus, a mobile terminal apparatus and a communication control method capable of selecting a CSI-RS arrangement flexibly in accordance with a system configuration. The base station apparatus has a CSI-RS arrangement section (211) configured to arrange a CSI-RS in a resource reserved for broadcasting when a mobile terminal apparatus (10) is notified of position information of the CSI-RS by broadcasting or in a resource associated with an cell ID of a serving area when the mobile terminal apparatus (10) obtains the position of the CSI-RS based on the cell ID; an identification information generating section (212) configured to generate an identification bit for identifying whether the CSI-RS is arranged in the resource reserved for broadcasting or in the resource associated with the cell ID; and a transmission/reception section (203) configured to transmit the identification information to the mobile terminal apparatus.
    Type: Grant
    Filed: June 10, 2011
    Date of Patent: January 20, 2015
    Assignee: NTT DoCoMo, Inc.
    Inventors: Tetsushi Abe, Nobuhiko Miki, Yusuke Ohwatari
  • Patent number: 8929232
    Abstract: A transmission power control method and a mobile station apparatus that can adequately control the transmission power of a mobile station apparatus having multiple transmitting antennas is disclosed. The uplink transmission power control for the mobile station apparatus measures the path loss of at least one transmitting antenna, sets a representative value path loss based on the measured path loss measurement value, determines a total transmission power of the mobile station apparatus based on the representative value path loss, and determines the transmission power of each transmitting antenna by distributing the total transmission power to the transmitting antennas.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: January 6, 2015
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yoshihisa Kishiyama, Daisuke Nishikawa, Tetsushi Abe, Nobuhiko Miki, Hiroyuki Ishii
  • Patent number: 8886204
    Abstract: A telecommunication control method for a heterogeneous network is provided. Uplink interference created by first user equipment (MUE) connected to a first-type cell (MeNB) is detected at the second-type cell (HeNB). The second-type cell reports the interference pattern of the detected interference to the first-type cell. The first-type cell identifies the interfering first user equipment based upon the interference pattern. The first-type cell notifies the second-type cell of the scheduling information of the interfering first user equipment. The second-type cell determines scheduling for second user equipment (HeUE) connected to the second-type cell based upon the scheduling information of the first user equipment.
    Type: Grant
    Filed: June 20, 2011
    Date of Patent: November 11, 2014
    Assignees: NTT DoCoMo, Inc., Agency for Science, Technology and Research
    Inventors: Daisuke Nishikawa, Tetsushi Abe, Motohiro Tanno, Zhongding Lei, Sai Ho Wong, Francois Po Shin Chin
  • Publication number: 20140307838
    Abstract: The IRC receiver 10 according to the present invention includes a channel estimation unit 11 that performs a channel estimation process so as to estimate a channel matrix H, a transmission weight matrix generation unit 13 that generates a transmission weight matrix WTx, a covariance matrix estimation unit 12 that estimates an interference signal covariance matrix (I) including a covariance matrix RI+N and an interference signal component on the basis of CRS, an IRC reception weight generation unit 14 that generates an IRC reception weight WIRC on the basis of the channel matrix H, the transmission weight matrix WTx, and the covariance matrix RI+N, and a received SINR estimation unit 15 that estimates received SINR on the basis of the channel matrix H, the interference signal covariance matrix (I), the transmission weight matrix WTx, and the IRC reception weight WIRC.
    Type: Application
    Filed: November 2, 2012
    Publication date: October 16, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Yuta Sagae, Yusuke Ohwatari, Nobuhiko Miki, Tetsushi Abe
  • Publication number: 20140307648
    Abstract: The present invention is designed to reduce the influence of performance deterioration due to interference when CoMP transmission is adopted in a heterogeneous network. A user terminal measures the first reception quality in the first transmission period when a macro base station performs no transmission or reduces transmission power, and second reception quality in a second transmission period when the macro base station and low power nodes perform transmission, and transmits an uplink signal including the first reception quality and the second reception quality, to the macro base station, and the macro base station receives the uplink signal including the first reception quality and the second reception quality, and, when performing the coordinated multiple-point transmission, allocates radio resources for a user terminal that is located on an edge of a coordinated area in the first transmission period, based on the first reception quality and the second reception quality.
    Type: Application
    Filed: August 14, 2012
    Publication date: October 16, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Satoshi Nagata, Tetsushi Abe, Nobuhiko Miki, Xiaoming She
  • Publication number: 20140301286
    Abstract: The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.
    Type: Application
    Filed: February 17, 2012
    Publication date: October 9, 2014
    Applicant: NTT DOCOMO, INC.
    Inventors: Tetsushi Abe, Yoshihisa Kishiyama, Satoshi Nagata, Nobuhiko Miki, Kazuaki Takeda