Patents by Inventor Daichi Imamura

Daichi Imamura 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: 10911198
    Abstract: Disclosed are a wireless transmitter and a reference signal transmission method that improve channel estimation accuracy. In a terminal, which transmits a reference signal using n (n is a non-negative integer 2 or greater) band blocks (which correspond to clusters here), which are disposed with spaces therebetween in a frequency direction, a reference signal controller switches the reference signal formation method of a reference signal generator between a first formation method and a second formation method based on the number (n) of band blocks. In addition, a threshold value setting unit adjusts a switching threshold value based on the frequency spacing between band blocks. Thus, the reference signal formation method can be selected with good accuracy and, as a result, channel estimation accuracy is further improved.
    Type: Grant
    Filed: February 27, 2019
    Date of Patent: February 2, 2021
    Assignee: Sun Patent Trust
    Inventors: Takashi Iwai, Sadaki Futagi, Tomohumi Takata, Daichi Imamura, Yoshihiko Ogawa
  • Patent number: 10912079
    Abstract: Where first and second reference signals for a first and second communication system, respectively, are transmitted, resources that affect a reception apparatus compatible only with the first communication system can be minimized, and the throughput can be prevented from being deteriorated. As resources for a reference signal CSI-RS for LTE-A, last half symbols in a time direction of a resource unit RB/Sub-frame defined in a frequency-time domain are used, and the CSI-RS is allocated in a position up to the last two symbols or in the last symbol, or the like, of a particular RB/Sub-frame and transmitted when a reference signal 4RS for LTE is transmitted to a reception apparatus in addition to transmitting CSI-RS for LTE-A. The reception apparatus receives CSI-RS allocated in the last half symbol of RB/Sub-frame based on CSI-RS allocation information, measures channel quality by using this CSI-RS, and transmits and reports feedback information.
    Type: Grant
    Filed: March 27, 2019
    Date of Patent: February 2, 2021
    Assignee: SUN PATENT TRUST
    Inventors: Masayuki Hoshino, Akihiko Nishio, Seigo Nakao, Daichi Imamura
  • Patent number: 10903947
    Abstract: A data alignment method capable of preventing degradation in demodulation performance due to variation in signal qualities when a data signal to which a Turbo code is applied is transmitted simultaneously from a plurality of cells. The method divides signal components to be used for data alignment into resources common to all the cells and resources dependent on the cells and transmits encoded and rate-matched data with the first half thereof aligned to the resources common to all the cells and the second half thereof aligned to the resources dependent on the cells.
    Type: Grant
    Filed: December 10, 2019
    Date of Patent: January 26, 2021
    Assignee: Sun Patent Trust
    Inventors: Masayuki Hoshino, Seigo Nakao, Daichi Imamura
  • Publication number: 20210022123
    Abstract: In a terminal, a control unit transmits a bundle response signal using a resource in a basic region of an uplink control channel in an uplink unit band of a unit band group when no error is detected in each of a plurality of pieces of downlink data of the unit band group, the uplink control channel in the uplink unit band being associated with a downlink control channel in a basic unit band that is a downlink unit band in which a broadcast channel signal including information relating to the uplink unit band is transmitted, and the control unit transmits the bundle response signal using a resource in an additional region of the uplink control channel when an error is detected in each of the plurality of pieces of downlink data.
    Type: Application
    Filed: September 30, 2020
    Publication date: January 21, 2021
    Inventors: Seigo Nakao, Daichi Imamura
  • Publication number: 20210014849
    Abstract: Provided are a radio transmission device and a radio transmission method capable of improving downlink and uplink throughput even when performing dynamic symbol allocation. In the device and the method, BS and MS share a table correlating a basic TF as a combination of parameters such as TB size used for transmitting only user data, an allocation RB quantity, a modulation method, and an encoding ratio, with a derived TF having user data of different TB size by combining L1/L2 control information. Even when multiplexing L1/L2 control information, Index corresponding to the basic TF is reported from BS to MS.
    Type: Application
    Filed: September 29, 2020
    Publication date: January 14, 2021
    Inventors: Daichi IMAMURA, Hidetoshi SUZUKI, Akihiko NISHIO, Atsushi MATSUMOTO
  • Publication number: 20210014030
    Abstract: Provided is a radio communication device which can prevent interference between SRS and PUCCH when the PUCCH transmission bandwidth fluctuates and suppress degradation of CQI estimation accuracy by the band where no SRS is transmitted. The device includes: an SRS code generation unit (201) which generates an SRS (Sounding Reference Signal) for measuring uplink line data channel quality; an SRS arrangement unit (202) which frequency-multiplexes the SRS on the SR transmission band and arranges it; and an SRS arrangement control unit (208) which controls SRS frequency multiplex so as to be uniform in frequency without modifying the bandwidth of one SRS multiplex unit in accordance with the fluctuation of the reference signal transmission bandwidth according to the SRS arrangement information transmitted from the base station and furthermore controls the transmission interval of the frequency-multiplexed SRS.
    Type: Application
    Filed: September 28, 2020
    Publication date: January 14, 2021
    Inventors: Atsushi Matsumoto, Daichi Imamura, Takashi Iwai, Yoshihiko Ogawa, Tomofumi Takata, Katsuhiko Hiramatsu
  • Publication number: 20210013982
    Abstract: A radio communication device capable of randomizing both inter-cell interference and intra-cell interference. In this device, a spreading section primarily spreads a response signal in a ZAC sequence set by a control unit. A spreading section secondarily spreads the primarily spread response signal in a block-wise spreading code sequence set by the control unit. The control unit controls the cyclic shift amount of the ZAC sequence used for the primary spreading in the spreading section and the block-wise spreading code sequence used for the secondary spreading in the spreading section according to a set hopping pattern. The hopping pattern set by the control unit is made up of two hierarchies. An LB-based hopping pattern different for each cell is defined in the first hierarchy in order to randomize the inter-cell interference. A hopping pattern different for each mobile station is defined in the second hierarchy to randomize the intra-cell interference.
    Type: Application
    Filed: September 25, 2020
    Publication date: January 14, 2021
    Inventors: Seigo Nakao, Daichi Imamura, Katsuhiko Hiramatsu
  • Publication number: 20210014031
    Abstract: It is possible to improve the CQI reception performance even when a delay is caused in a propagation path, a transmission timing error is caused, or a residual interference is generated between cyclic shift amounts of different ZC sequences. For the second symbol and the sixth symbol of the ACK/NACK signal which are multiplexed by RS of CQI, (+, +) or (?, ?) is applied to a partial sequence of the Walsh sequence. For RS of CQI transmitted from a mobile station, + is added as an RS phase of the second symbol and ? is added as an RS phase of the sixth symbol. A base station (100) receives multiplexed signals of ACK/NACK signals and CQI signals transmitted from a plurality of mobile stations. An RS synthesis unit (119) performs synthesis by aligning the RS phase of CQI.
    Type: Application
    Filed: September 29, 2020
    Publication date: January 14, 2021
    Inventors: Seigo Nakao, Daichi Imamura, Yoshihiko Ogawa, Atsushi Matsumoto, Katsuhiko Hiramatsu
  • Publication number: 20210013983
    Abstract: Provided are a wireless communication apparatus and a reference signal generating method, wherein inter-cell interference is reduced inside and outside a CoMP set. A CoMP mode setting unit (101) sets whether the terminal (100) thereof is a CoMP terminal or a Non-CoMP terminal. When the terminal (100) is set as a Non-CoMP terminal, the hopping pattern calculating unit (104) calculates a ZC sequence number to be used as the transmission timing, from among all the ZC sequence numbers that can be used within the system. When the terminal (100) is set as a CoMP terminal, the hopping pattern calculating unit (104) calculates a ZC sequence number to be used as the transmission timing, by hopping the ZC sequence numbers to be used within the CoMP set. A ZC sequence generating unit (105) generates a ZC sequence to be used as an SRS, using the calculated ZC sequence number.
    Type: Application
    Filed: September 30, 2020
    Publication date: January 14, 2021
    Inventors: Takashi Iwai, Daichi Imamura, Akihiko Nishio, Yoshihiko Ogawa, Masaru Fukuoka
  • Publication number: 20210006312
    Abstract: The present disclosure provides a method of generating codebook in a wireless communication system with multiple antenna arrays, as well as a wireless communication system, base station and terminal using the codebook for communication. The method comprises steps of: providing a basic codebook which contains multiple pre-coding matrices; and assigning phase offsets to certain pre-coding matrices in the basic codebook to form a codebook with phase offset. The feedback overhead from a client to a base station side is reduced and a good precision of feedback for multi-antenna array is kept by applying the method of generating codebook and using the generated codebook in the wireless communication system, base station and terminal.
    Type: Application
    Filed: September 23, 2020
    Publication date: January 7, 2021
    Inventors: Hui Tong, Masayuki Hoshino, Ming Xu, Seigo Nakao, Daichi Imamura
  • Patent number: 10873913
    Abstract: Disclosed is a wireless communication device that can suppress an increase in power consumption of a terminal while preventing the degradation of SINR measurement precision resulting from TPC errors in a base station. A terminal controls the transmission power of a second signal by adding an offset to the transmission power of a first signal; an offset-setting unit sets an offset correction value in response to a transmission time gap between a third signal transmitted the previous time and the second signal transmitted this time; and a transmission power control unit controls the transmission power of the second signal using the correction value.
    Type: Grant
    Filed: October 29, 2019
    Date of Patent: December 22, 2020
    Assignee: Sun Patent Trust
    Inventors: Takashi Iwai, Daichi Imamura, Akihiko Nishio, Yoshihiko Ogawa, Shinsuke Takaoka
  • Publication number: 20200396016
    Abstract: A terminal apparatus includes circuitry and a transmitter. The circuitry, in operation, generates a reference signal using a cyclic shift value and an orthogonal sequence, which are associated with each other. The orthogonal sequence is one of two orthogonal sequences corresponding to a first orthogonal sequence [1, 1] and a second orthogonal sequence [1, ?1]. The cyclic shift value is one of 12 cyclic shift values ranging from 0 to 11. The transmitter, in operation, transmits the reference signal multiplexed with a data signal. Two of the cyclic shift values having a difference of 6 are respectively associated with the two orthogonal sequences.
    Type: Application
    Filed: August 27, 2020
    Publication date: December 17, 2020
    Inventors: Yoshihiko Ogawa, Akihiko Nishio, Takashi Iwai, Seigo Nakao, Daichi Imamura, Atsushi Sumasu
  • Publication number: 20200389913
    Abstract: A base station able to maintain backward compatibility with an LTE mobile station while minimizing the amount of increase in uplink scheduling information reception and demodulation/decoding processing in independent uplink/downlink cell data transmission. A wireless communication system includes a cell #1, a cell #2, and an LTE-A mobile station, and supports independent uplink/downlink cell data transmission. The base station of the cell #2 arranges a PDCCH+, which includes uplink scheduling information from the LTE-A mobile station to the base station of the cell #2, in a downlink data region in the downlink connection of the base station of the cell #1.
    Type: Application
    Filed: August 24, 2020
    Publication date: December 10, 2020
    Inventors: Atsushi SUMASU, Shozo OKASAKA, Shinsuke TAKAOKA, Seigo NAKAO, Daichi IMAMURA
  • Patent number: 10863448
    Abstract: Provided is a communication device, which is enabled to improve the throughput of a communication system by reducing the difference of a transmission power between an SCCH and an SDCH thereby to satisfy the required quality of a PAPR. In this device, an MCS selection unit (111) of a transmission unit (110) decides, with reference to a CQI lookup table, an MCS pattern (MCS1) of the SDCH, an MCS pattern (MCS2) of the SCCH and information (multiplex information) on multiplex positions on the time axes of those two channels, on the basis of the CQI information. On the basis of the MCS2 and the MCS1, encoding modulation units (112 and 113) perform encoding and modulating operations. According to the multiplex information, a channel multiplexing unit (114) time-division multiplexes the SCCH and the SDCH thereby to generate a transmission signal.
    Type: Grant
    Filed: October 9, 2019
    Date of Patent: December 8, 2020
    Assignee: Optis Wireless Technology, LLC
    Inventors: Sadaki Futagi, Daichi Imamura, Atsushi Matsumoto, Takashi Iwai
  • Publication number: 20200359423
    Abstract: A radio performs random access by receiving control information and grouping a predetermined number of sequences that are generated from a plurality of base sequences into a plurality of groups by partitioning the predetermined number of sequences. At least one of the groups is associated with a first respective range of data amounts and a first respective range of reception qualities. Sequences generated from a common base sequence are arranged in an increasing order of respective cyclic shifts associated with the sequences. A sequence is randomly selected from a plurality of sequences contained in one group of the plurality of groups. A position at which the predetermined number of sequences are partitioned is determined based on the control information. A number of sequences contained in each of the plurality of groups varies in accordance with the control information.
    Type: Application
    Filed: July 30, 2020
    Publication date: November 12, 2020
    Inventors: Daichi Imamura, Sadaki Futagi, Atsushi Matsumoto, Takashi Iwai, Tomofumi Takata
  • Patent number: 10833741
    Abstract: The present disclosure provides a method of generating codebook in a wireless communication system with multiple antenna arrays, as well as a wireless communication system, base station and terminal using the codebook for communication. The method comprises steps of: providing a basic codebook which contains multiple pre-coding matrices; and assigning phase offsets to certain pre-coding matrices in the basic codebook to form a codebook with phase offset. The feedback overhead from a client to a base station side is reduced and a good precision of feedback for multi-antenna array is kept by applying the method of generating codebook and using the generated codebook in the wireless communication system, base station and terminal.
    Type: Grant
    Filed: February 28, 2020
    Date of Patent: November 10, 2020
    Assignee: Sun Patent Trust
    Inventors: Hui Tong, Masayuki Hoshino, Ming Xu, Seigo Nakao, Daichi Imamura
  • Patent number: 10826668
    Abstract: Provided is a radio communication device which can prevent interference between SRS and PUCCH when the PUCCH transmission bandwidth fluctuates and suppress degradation of CQI estimation accuracy by the band where no SRS is transmitted. The device includes: an SRS code generation unit (201) which generates an SRS (Sounding Reference Signal) for measuring uplink line data channel quality; an SRS arrangement unit (202) which frequency-multiplexes the SRS on the SR transmission band and arranges it; and an SRS arrangement control unit (208) which controls SRS frequency multiplex so as to be uniform in frequency without modifying the bandwidth of one SRS multiplex unit in accordance with the fluctuation of the reference signal transmission bandwidth according to the SRS arrangement information transmitted from the base station and furthermore controls the transmission interval of the frequency-multiplexed SRS.
    Type: Grant
    Filed: January 4, 2018
    Date of Patent: November 3, 2020
    Assignee: Panasonic Corporation
    Inventors: Atsushi Matsumoto, Daichi Imamura, Takashi Iwai, Yoshihiko Ogawa, Tomofumi Takata, Katsuhiko Hiramatsu
  • Patent number: 10826669
    Abstract: It is possible to improve the CQI reception performance even when a delay is caused in a propagation path, a transmission timing error is caused, or a residual interference is generated between cyclic shift amounts of different ZC sequences. For the second symbol and the sixth symbol of the ACK/NACK signal which are multiplexed by RS of CQI, (+, +) or (?, ?) is applied to a partial sequence of the Walsh sequence. For RS of CQI transmitted from a mobile station, + is added as an RS phase of the second symbol and ? is added as an RS phase of the sixth symbol. A base station (100) receives multiplexed signals of ACK/NACK signals and CQI signals transmitted from a plurality of mobile stations. An RS synthesis unit (119) performs synthesis by aligning the RS phase of CQI.
    Type: Grant
    Filed: November 16, 2018
    Date of Patent: November 3, 2020
    Assignee: Godo Kaisha IP Bridge 1
    Inventors: Seigo Nakao, Daichi Imamura, Yoshihiko Ogawa, Atsushi Matsumoto, Katsuhiko Hiramatsu
  • Patent number: 10827466
    Abstract: Provided are a radio transmission device and a radio transmission method capable of improving downlink and uplink throughput even when performing dynamic symbol allocation. In the device and the method, BS and MS share a table correlating a basic TF as a combination of parameters such as TB size used for transmitting only user data, an allocation RB quantity, a modulation method, and an encoding ratio, with a derived TF having user data of different TB size by combining L1/L2 control information. Even when multiplexing L1/L2 control information, Index corresponding to the basic TF is reported from BS to MS.
    Type: Grant
    Filed: July 21, 2016
    Date of Patent: November 3, 2020
    Assignee: Panasonic Corporation
    Inventors: Daichi Imamura, Hidetoshi Suzuki, Akihiko Nishio, Atsushi Matsumoto
  • Patent number: 10826638
    Abstract: Provided are a wireless communication apparatus and a reference signal generating method, wherein inter-cell interference is reduced inside and outside a CoMP set. A CoMP mode setting unit (101) sets whether the terminal (100) thereof is a CoMP terminal or a Non-CoMP terminal. When the terminal (100) is set as a Non-CoMP terminal, the hopping pattern calculating unit (104) calculates a ZC sequence number to be used as the transmission timing, from among all the ZC sequence numbers that can be used within the system. When the terminal (100) is set as a CoMP terminal, the hopping pattern calculating unit (104) calculates a ZC sequence number to be used as the transmission timing, by hopping the ZC sequence numbers to be used within the CoMP set. A ZC sequence generating unit (105) generates a ZC sequence to be used as an SRS, using the calculated ZC sequence number.
    Type: Grant
    Filed: March 25, 2019
    Date of Patent: November 3, 2020
    Assignee: SUN PATENT TRUST
    Inventors: Takashi Iwai, Daichi Imamura, Akihiko Nishio, Yoshihiko Ogawa, Masaru Fukuoka