Patents by Inventor Hidetoshi Kayama

Hidetoshi Kayama 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: 8553665
    Abstract: A method for accessing a hybrid network and a gateway communication system are disclosed. The method comprises: sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wide area network; transmitting by a wireless terminal a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and if the relay request signal from the wireless terminal is sensed in the relay request slot, establishing by the gateway apparatus a connection with the wireless terminal in a distributed network environment. As such, the gateway apparatus accesses the wireless distributed network only when the surrounding wireless terminals require data relay, without sensing signals on both networks simultaneously.
    Type: Grant
    Filed: March 12, 2012
    Date of Patent: October 8, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lei Du, Yong Bai, Lan Chen, Hidetoshi Kayama
  • Publication number: 20130229296
    Abstract: A multi-beam reflectarray includes two or more element arrays including plural elements aligned along a predetermined direction. The multi-beam reflectarray is such that, in each of a first element group and a second element group included in at least one of the element arrays, a difference between phases of radio waves reflected by corresponding two elements is in proportion to a first product of a distance between the two elements and a value of a trigonometric function with respect to an angle of reflection by the two elements, and a distance between neighboring elements in the first element group is equal to a product of a rational number and a distance between neighboring elements in the second element group.
    Type: Application
    Filed: August 15, 2012
    Publication date: September 5, 2013
    Applicant: NTT DOCOMO, INC.
    Inventors: Tamami Maruyama, Yasuhiro Oda, Jiyun Shen, Ngoc Hao Tran, Hidetoshi Kayama
  • Patent number: 8432994
    Abstract: The present invention discloses a method for determining an uplink demodulation reference signal (DMRS), which includes: taking one of multiple transmit antennas in the uplink as a base transmit antenna, taking other transmit antennas as subordinating transmit antennas and setting a DMRS for the base transmit antenna; establishing DMRS subordinating relationships between the base transmit antenna and each of the subordinating transmit antennas; and setting a DMRS for each of the subordinating transmit antennas according to the DMRS of the base transmit antenna and the DMRS subordinating relationship between the base transmit antenna and each of the subordinating transmit antennas. The present invention also provides a user equipment (UE) and an uplink system for providing DMRSs for multiple transmit antennas. The method, UE and system are applicable in both SU-MIMO transmission and MU-MIMO transmission.
    Type: Grant
    Filed: July 13, 2010
    Date of Patent: April 30, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Xiaolin Hou, Zhan Zhang, Hidetoshi Kayama
  • Patent number: 8385453
    Abstract: A data processing method and a base station for downlink transmit diversity are disclosed. One embodiment of the method comprises: obtaining data symbol groups formed by arranging a first type data symbol and a second type data symbol in an interval, wherein the first type data symbol is more important; determining a first antenna port pairing mode corresponding to a current slot; performing, for OFDM symbols including the reference signal in the current slot, an antenna port and subcarrier mapping on symbols in a transmit diversity matrix corresponding to the data symbol groups according to the first antenna port pairing mode, wherein a subcarrier in which a symbol related to the first type data symbol is located is nearer to a subcarrier in which a reference signal at the same antenna port is located; and performing an inverse fast fourier transform and a cyclic prefix insertion processing on symbols mapped to subcarriers and then mapping the time domain symbols to a physical antenna for transmission.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: February 26, 2013
    Assignee: NTT DoCoMo, Inc.
    Inventors: Anxin Li, Yuan Yan, Xinying Gao, Hidetoshi Kayama
  • Patent number: 8311022
    Abstract: A method for accessing a hybrid network including a wide area network and a distributed network, a gateway apparatus, a wireless terminal and a gateway communication system are disclosed for reducing the power consumption of the wireless terminal which is an access gateway. The method comprises: sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wide area network; transmitting by a wireless terminal a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and if the relay request signal from the wireless terminal is sensed in the relay request slot, establishing by the gateway apparatus a connection with the wireless terminal in a distributed network environment.
    Type: Grant
    Filed: September 21, 2009
    Date of Patent: November 13, 2012
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lei Du, Yong Bai, Lan Chen, Hidetoshi Kayama
  • Publication number: 20120213102
    Abstract: A wireless station in a second communication system, with at least a portion of a first frequency band used in a first communication system and a portion of a second frequency band used in the second communication system being shared or neighboring, the wireless station including a waveform characteristic quantity extracting unit that extracts a waveform characteristic quantity which shows a statistical characteristic of a signal received from the first communication system; a communication parameter determining unit that determines communication parameters to be used for the wireless station in the second communication system depending on a determination result of whether the extracted waveform characteristic quantity is of a predetermined waveform characteristic quantity for reducing an interference; and a transmission and reception unit that transmits and receives a wireless communication signal in the second communication system in accordance with the determined communication parameters.
    Type: Application
    Filed: January 13, 2012
    Publication date: August 23, 2012
    Applicant: NTT DOCOMO, INC.
    Inventors: Hiroki Harada, Hiromasa Fujii, Shunji Miura, Hidetoshi Kayama
  • Publication number: 20120214525
    Abstract: A CRS base station (21) includes a transmitting section configured to transmit a synchronization establishment signal, a receiving section configured to receive a random access signal corresponding to the synchronization establishment signal, a determining section configured to determine whether or not the random access signal received by the receiving section has been transmitted from an MCS terminal (12) and an interference reduction processing section configured to perform interference reduction processing on the MCS terminal (12) when the determining section determines that the random access signal has been transmitted from the MCS terminal (12).
    Type: Application
    Filed: January 30, 2012
    Publication date: August 23, 2012
    Applicant: NTT DOCOMO, INC.
    Inventors: Hiromasa FUJII, Hiroto Yasuda, Hiroki Harada, Shunji Miura, Hidetoshi Kayama
  • Publication number: 20120207049
    Abstract: A method for accessing a hybrid network and a gateway communication system are disclosed. The method comprises: sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wide area network; transmitting by a wireless terminal a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and if the relay request signal from the wireless terminal is sensed in the relay request slot, establishing by the gateway apparatus a connection with the wireless terminal in a distributed network environment. As such, the gateway apparatus accesses the wireless distributed network only when the surrounding wireless terminals require data relay, without sensing signals on both networks simultaneously.
    Type: Application
    Filed: March 12, 2012
    Publication date: August 16, 2012
    Inventors: Lei Du, Yong Bai, Lan Chen, Hidetoshi Kayama
  • Patent number: 8160048
    Abstract: A method for accessing a hybrid network including a wide area network and a distributed network, a gateway apparatus, a wireless terminal and a gateway communication system are disclosed for reducing the power consumption of the wireless terminal which is an access gateway. The method comprises: sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wide area network; transmitting by a wireless terminal a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and if the relay request signal from the wireless terminal is sensed in the relay request slot, establishing by the gateway apparatus a connection with the wireless terminal in a distributed network environment.
    Type: Grant
    Filed: October 18, 2006
    Date of Patent: April 17, 2012
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lei Du, Yong Bai, Lan Chen, Hidetoshi Kayama
  • Patent number: 8111652
    Abstract: A base station comprises a packet classification unit configured to classify packets received/transmitted from/to a plurality of mobile stations into a quantitative guarantee type packet having a request value for communication quality or a relative guarantee type packet not having the request value, and a transmission order controller configured to control a transmission order of the packets for every classified quantitative guarantee type packet and every classified relative guarantee type packet.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: February 7, 2012
    Assignee: NTT DoCoMo, Inc.
    Inventors: Daisuke Kitazawa, Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 8107439
    Abstract: The present invention discloses a method and apparatus of physical resource allocation as well as a method of data receiving and a receiving end in a wireless communication system. The method of physical resource allocation includes: detecting a pilot signal sent by each user within a designated range; obtaining received power of the pilot signal sent by each user; scheduling each user within the designated range to obtain a user group including at least one user according to the received power; and allocating a same physical resource to each user of the user group. According to the method and the apparatus, it is possible to reuse a physical resource and sequentially decode data packets corresponding to users in a user group occupying the same physical resource according to the Capture Effect and interference cancellation technology, thereby improving the spectrum efficiency and throughput of uplink or downlink greatly.
    Type: Grant
    Filed: March 2, 2009
    Date of Patent: January 31, 2012
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yuan Yan, Anxin Li, Xiangming Li, Hidetoshi Kayama
  • Patent number: 7970349
    Abstract: The present invention improves a system capacity and satisfaction rate with a quality of service in packet communications performed through a radio link established between a transmitting station and a receiving station by dynamically limiting transmission power of packets in the transmitting station and keeping an increase of an interference level in the receiving station, which belongs to another cell, within a TPC margin. The present invention includes a resource allocator 115 configured to set transmission power of packets in a next step period, by use of transmission power of packets in a preceding step period (slot) and an interference level of the receiving station.
    Type: Grant
    Filed: November 18, 2008
    Date of Patent: June 28, 2011
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Daisuke Kitazawa, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7965785
    Abstract: A method is provided for MIMO uplink communications between a base station and a wireless station with more than two antennae. The method includes: (a) negotiating between the base station and the wireless station uplink MIMO/cooperative MIMO capabilities, using a message exchange protocol in which a message exchanged comprises a field for specifying uplink MIMO/cooperative MIMO capabilities; (b) the base station receiving a request from the wireless station for data transmission; (c) the base station sending the wireless station an allocated resource and an uplink MIMO/cooperative MIMO method for uplink transmission; (e) the wireless station mapping data symbols to the allocated resource with proper pilot pattern; and (f) the base station detecting the data symbols from the channel.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: June 21, 2011
    Assignee: NTT DOCOMO, Inc.
    Inventors: Anxin Li, Xiangming Li, Hidetoshi Kayama, Ismail Guvenc, Moo Ryong Jeong
  • Publication number: 20110013713
    Abstract: A data processing method and a base station for downlink transmit diversity are disclosed. One embodiment of the method comprises: obtaining data symbol groups formed by arranging a first type data symbol and a second type data symbol in an interval, wherein the first type data symbol is more important; determining a first antenna port paring mode corresponding to a current slot; performing, for OFDM symbols including reference signals in the current slot, an antenna port and subcarrier mapping on symbols in a transmit diversity matrix corresponding to the data symbol group according to the first antenna port paring mode, wherein a subcarrier in which a symbol related to the first type data symbol is located is nearer to a subcarrier in which a reference signal at the same antenna port is located; and performing an inverse fast fourier transform and a cyclic prefix insertion processing on symbols mapped to subcarriers and then mapping the symbols to a physical antenna for transmission.
    Type: Application
    Filed: July 9, 2010
    Publication date: January 20, 2011
    Inventors: Anxin Li, Yuan Yan, Xinying Gao, Hidetoshi Kayama
  • Publication number: 20110002412
    Abstract: The present invention discloses a method for determining an uplink demodulation reference signal (DMRS), which includes: taking one of multiple transmit antennas in the uplink as a base transmit antenna, taking other transmit antennas as subordinating transmit antennas and setting a DMRS for the base transmit antenna; establishing DMRS subordinating relationships between the base transmit antenna and each of the subordinating transmit antennas; and setting a DMRS for each of the subordinating transmit antennas according to the DMRS of the base transmit antenna and the DMRS subordinating relationship between the base transmit antenna and each of the subordinating transmit antennas. The present invention also provides a user equipment (UE) and an uplink system for providing DMRSs for multiple transmit antennas. The method, UE and system are applicable in both SU-MIMO transmission and MU-MIMO transmission.
    Type: Application
    Filed: July 13, 2010
    Publication date: January 6, 2011
    Inventors: Xiaolin HOU, Zhan Zhang, Hidetoshi Kayama
  • Patent number: 7821982
    Abstract: A base station includes a channel quality detecting unit that detects channel quality between the base station and a mobile station, a buffered data amount monitoring unit, and a modulation and coding set determination unit. The modulation and coding set determination unit determines a modulation and coding set, as a downlink modulation scheme for packet communications, such that a prescribed communication condition corresponding to the channel quality is satisfied, and that padding added to the data buffered in a transmission buffer for subsequent transmission to the mobile station becomes the minimum.
    Type: Grant
    Filed: December 17, 2003
    Date of Patent: October 26, 2010
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20100254263
    Abstract: In packet communications between a mobile terminal and a base station, the mobile terminal checks a priority level of a traffic and judges a type of the traffic, and transmits a reservation signal for a transmission request to the base station when the type of the traffic is a high priority level or realtime type, and does not transmits it when the type of the traffic is a low priority level or non-realtime type, while the base station determines a resource amount to be reserved for packet transmission according to a resource utilization state and the reservation signal for the traffic of the high priority level or realtime type, or an average transmission interval or transmission rate for the traffic of the low priority level or non-realtime type according to margins in remaining resources, and notifies the resource amount or the average transmission interval or transmission rate to the mobile terminal.
    Type: Application
    Filed: March 18, 2010
    Publication date: October 7, 2010
    Applicant: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20100246524
    Abstract: Embodiments of the present invention include a method, system and transmitter for adaptive coordinated transmission in wireless communications. The method includes: determining more than one transmitter for performing coordinated transmission, configuring one of the more than one transmitter to be a serving transmitter with others of the more than one transmitter being cooperating transmitters, and determining more than one receiver; determining, by a cooperating transmitter, a cooperation mode according to measured signal parameters of the more than one receiver after receiving a cooperation request from the serving transmitter, and providing the cooperation mode to the serving transmitter; generating, by each of the more than one transmitter, a transmit signal corresponding to the more than one receiver according to the cooperation mode determined, and transmitting the transmit signal to each of the more than one receiver.
    Type: Application
    Filed: March 26, 2010
    Publication date: September 30, 2010
    Inventors: Xiaolin Hou, Zhan Zhang, Hidetoshi Kayama
  • Patent number: 7801482
    Abstract: The present invention improves a system capacity and satisfaction rate with a quality of service in packet communications performed through a radio link established between a transmitting station and a receiving station by dynamically limiting transmission power of packets in the transmitting station and keeping an increase of an interference level in the receiving station, which belongs to another cell, within a TPC margin. The present invention includes a resource allocator 115 configured to set transmission power of packets in a next step period, by use of transmission power of packets in a preceding step period (slot) and an interference level of the receiving station.
    Type: Grant
    Filed: November 18, 2008
    Date of Patent: September 21, 2010
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Daisuke Kitazawa, Hidetoshi Kayama, Narumi Umeda
  • Patent number: RE43593
    Abstract: A base station includes: an acquisition unit for acquiring a quantity of stored packets from a mobile station, the quantity of stored packets being stored in a buffer for storing the packets transmitted by the mobile station; a radio resource controller for allocating priority radio resources preferentially usable by the mobile station to a radio channel for the mobile station, and for allocating usable radio resources allowed to be used by the mobile station from the priority radio resources to the mobile station by use of the quantity of stored packets acquired by the acquisition unit; and a result notification unit for reporting a result of the allocation by the radio resource controller to the mobile station.
    Type: Grant
    Filed: April 14, 2010
    Date of Patent: August 21, 2012
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidetoshi Kayama, Lan Chen, Narumi Umeda