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: 7453841
    Abstract: A scramble code allocation method used by mobile communications systems, and a base station and a mobile station that use the method are disclosed. The scramble code allocation method autonomously and optimally sets up a scramble code unique to a target base station. The method includes a step of generating a collection packet for collecting unique information of surrounding base stations, the unique information being used for setting up respective identifiers of the surrounding base stations; a step of broadcasting the collection packet to the surrounding base stations through a network; a step of receiving response packets from the surrounding base stations in response to the collection packet; a step of extracting the unique information of the surrounding base stations inserted in the response packets that are received; a step of storing the extracted unique information; and a step of setting up an identifier of the target base station based on the stored unique information.
    Type: Grant
    Filed: November 5, 2004
    Date of Patent: November 18, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masayuki Motegi, Takeshi Yamashita, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20080247488
    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: Application
    Filed: October 31, 2007
    Publication date: October 9, 2008
    Inventors: Anxin Li, Xiangming Li, Hidetoshi Kayama, Ismail Guvenc, Moo Ryong Jeong
  • Patent number: 7417963
    Abstract: An object of the present invention is to enable the improvement of Qos and efficient use of resources with regard to the entire system by performing resource control of an own cell in cooperation with that of peripheral cells. The present invention provides a resource control system used for packet communication between a mobile station and each of a first and a second base stations. The first base station includes the judgment unit for judging whether or not the Qos of a packet to be communicated with the mobile station is ensured in the packet communication with the mobile station, or judging whether or not the resources necessary for a packet to be communicated with the mobile station are secured; and the second base station interface for requesting the second base station to suppress the use of resources when the Qos is judged not to be ensured, or the necessary resources are judged not to be secured.
    Type: Grant
    Filed: December 18, 2002
    Date of Patent: August 26, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7394785
    Abstract: In a mobile communication system 1 having a radio base station 2, and mobile stations 5, 6 configured to communicate with the base station 2 and segmented into a plurality of mobile station groups, the base station 5 provides a broadcast channel with first instruction information to notify the mobile station 5 of whether or not to receive the broadcast channel, provides a paging channel with second instruction information to notify the mobile station 5 of the presence/absence of paging information, and performs such a channel transmission control as to intermittently transmit the broadcast channel and the paging channel on a control channel.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: July 1, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masayuki Motegi, Hideki Tobe, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7366130
    Abstract: In a disclosed mobile communications system wherein packet communication between a base station and its subordinated mobile station is established based on a reservation packet, the packet communication uses controlled transmission power and a radio resource allocated based on reception quality information received from the mobile station.
    Type: Grant
    Filed: November 5, 2004
    Date of Patent: April 29, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Heng Qiu, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7359349
    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: November 20, 2002
    Date of Patent: April 15, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidetoshi Kayama, Lan Chen, Narumi Umeda
  • Publication number: 20080013641
    Abstract: One embodiment of the present invention provides a data transmission method, including: performing a serial-to-parallel conversion for input date stream, obtaining 4 parallel data streams and partitioning the 4 parallel data streams into 2 groups; performing trellis encoding for one group and selecting one basic codeword subset from all basic codeword subsets according to the trellis encoding output; performing trellis encoding for one data stream in the other group and selecting one phase subset from all phase subsets according to the trellis encoding output, and selecting a phase value from the selected phase subset according to another data stream in the other group; rotating the codeword selected from the basic codeword subset by the selected phase value and obtaining and transmitting an output codeword to a data receive-side. One embodiment of the present invention also includes another data transmission method and two data transmission apparatuses.
    Type: Application
    Filed: June 21, 2007
    Publication date: January 17, 2008
    Inventors: Anxin Li, Mingshu Wang, Xiangming Li, Hidetoshi Kayama
  • Publication number: 20080002566
    Abstract: An embodiment of the present invention includes a method for generating a training sequence for joint frame synchronization and carrier frequency offset estimation and a communication system and method using the training sequence. In one embodiment, the training sequence includes a first training symbol and a second training symbol of equal-length, but without a cyclic prefix (CP). One embodiment of the method for generating the training sequence includes generating the first training symbol randomly according to a method for generating normal data symbols; subdividing the generated first training symbol logically into M sub-blocks with equal-length, wherein the structure characteristic M is a natural number larger than or equal to 1 and less than or equal to N; and copying the M sub-blocks in an reverse order to form the second training symbol, which together with the first training symbol constitute the training sequence.
    Type: Application
    Filed: June 29, 2006
    Publication date: January 3, 2008
    Inventors: Zhongshan Zhang, Hidetoshi Kayama
  • Publication number: 20070291640
    Abstract: Embodiments of the present invention include a system and method of dynamic space-frequency-division multiple-access for the uplink from terminals to a base-station. The system includes a base-station and multiple terminals. According to different spatial mapping modes, the base-station performs an optimization computation using an optimization function in order to obtain control information for controlling terminals; after receiving the control information, the user terminal controls the transmitting mode using this control information. The method includes the following operations: at the base-station, performing an optimization computation using an optimization function according to different spatial mapping modes respectively, in order to obtain control information for controlling terminals; at the user terminal, controlling a transmitting mode using the control information after receiving the above control information.
    Type: Application
    Filed: December 28, 2006
    Publication date: December 20, 2007
    Inventors: Zhan Zhang, Hidetoshi Kayama
  • Patent number: 7308282
    Abstract: It is an object to control the traffic that flows in a radio link to ensure the stability of the network as well as to prevent the deterioration of the communication quality due to the transmission of packets exceeding the capacity, and to increase the communication capacity. A communication control system in a packet mobile communication transmits a downlink packet from a base station to a mobile station via a radio network. The base station includes a transmission determiner that determines whether or not to transmit the downlink packet to the radio network in accordance with the state of congestion of the radio network and the traffic type (DSCP) of the downlink packet.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: December 11, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7292863
    Abstract: A method is disclosed that is capable of appropriately assigning radio resource even when a propagation quality changes. After receiving the required communication rate from the mobile station, the base station measures the maximum used radio resource, and multiplies the maximum used radio resource by a factor ?. Next, the base station subtracts the above result from the total radio resource and obtains the maximum assignable radio resource. Then, the base station calculates an admissible communication rate based on the maximum assignable radio resources. Then, if the required communication rate is less than or equal to the admissible communication rate, the base station admits the request.
    Type: Grant
    Filed: November 18, 2003
    Date of Patent: November 6, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20070206699
    Abstract: Embodiments of the present invention provides an adaptive space-time coding and modulation method and a transmitter. In one embodiment, the method includes: obtaining a curve corresponding to a modulation mode, a channel coding rate, a coding mode of a space-time code, a parameter indicating signal transmission quality and SNR by simulating or measuring at transmit-side and making a table with correspondences between the SNR, the modulation mode and the coding mode of the space-time code according to a SNR range corresponding to a predefined signal transmission quality. Higher frequency spectrum efficiency can be achieved with the quality of service guaranteed.
    Type: Application
    Filed: March 1, 2007
    Publication date: September 6, 2007
    Inventors: Chunlin Yan, Zhan Zhang, Hidetoshi Kayama
  • Patent number: 7239619
    Abstract: Provided is a mobile communication system capable of reducing interference in uplinks and downlinks to achieve excellent communication quality. A mobile station receives cell selection reference signals from a first base station and a second base station to connect before and after a handover, and measures received power values of the cell selection reference signals. The mobile station acquires uplink transmitted power values from the mobile station to the first base station and to the second base station. The first base station and the second base station control a power of the cell selection reference signal so that the uplink transmitted power values from the mobile station to the first base station and to the second base station become substantially equal and so that a received power value at the mobile station of the cell selection reference signal becomes substantially equal to a predetermined reference power value.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: July 3, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hideki Tobe, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7218950
    Abstract: An object of the present invention is to reduce the volume of a control signal and shorten a delay of processing in a system comprising a base station configured to transmit a pilot signal at a predetermined transmission power and a mobile station configured to transmit a preamble prior to transmission/reception of data.
    Type: Grant
    Filed: April 8, 2004
    Date of Patent: May 15, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Heng Qiu, Hidetoshi Kayama, Jyunichirou Hagiwara, Narumi Umeda
  • Publication number: 20070098009
    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: Application
    Filed: October 18, 2006
    Publication date: May 3, 2007
    Inventors: Lei Du, Yong Bai, Lan Chen, Hidetoshi Kayama
  • Patent number: 7184709
    Abstract: A base station includes an adjacent cell interference amount calculator and an adjacent cell interference amount notifier. The adjacent cell interference amount calculator calculates an adjacent cell interference amount caused by an adjacent cell adjacent to an original cell managed by the base station. The adjacent cell interference amount notifier notifies the mobile station of the adjacent cell interference amount. A mobile station includes radio resource associators, a selector, a propagation loss calculator, and a radio resource assigner. The radio resource associators associate a radio resource with a propagation loss in the radio packet communication. The selector selects a radio resource associator in accordance with the adjacent cell interference amount. The propagation loss calculator calculates a propagation loss in the radio packet communication.
    Type: Grant
    Filed: February 24, 2004
    Date of Patent: February 27, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Heng Qiu, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20060269007
    Abstract: A method for generating a cyclic training sequence and a communication method and system using the cyclic training sequence are disclosed.
    Type: Application
    Filed: May 23, 2006
    Publication date: November 30, 2006
    Inventors: Zhongsham Zhang, Hidetoshi Kayama
  • Patent number: 7117003
    Abstract: The present invention allows transmission power control for each packet without increasing overhead and control processing delay in communications control systems such as CDMA systems, thereby increasing the quality of transmission. The present invention provides a communications control system for controlling packet communications between a base station and a mobile station, including a determiner for determining the transmission power level of packet data based on the received intensity of a preamble signal transmitted in advance of transmission of the packet data or a reservation signal, a reservation signal transmitter for transmitting to the base station information regarding the amount and type of subsequent packet data as the reservation signal in parallel with transmission processing of the packet data, and a packet data transmitter for obtaining information regarding the determined transmission power level at the mobile station and transmitting the packet data based on the obtained information.
    Type: Grant
    Filed: November 21, 2002
    Date of Patent: October 3, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7110767
    Abstract: For realizing a mobile communication network highly compatible with the Internet and improving channel efficiency and battery conservation in a mobile communication system including a plurality of base stations connected to IP network, a plurality of mobile stations locating in a cell formed by base station, and a server, connected to the IP network, for managing location information of the mobile stations, wherein a set of cells constitutes a paging area, whereas the server manages information of a standby mobile station as location information of mobile stations about paging area in which mobile station locates; the server determines whether a mobile station is in standby state or not when a base station transfers to the server a packet addressed to the mobile station and, if the mobile station is in the standby state, copies the packet by the number of the base stations corresponding to the paging area related to the mobile station and multicasts thus copied packets.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: September 19, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masayuki Motegi, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 7089017
    Abstract: To provide a service with fairness by providing QoS of approximately an equal degree among users of the same service class to keep fairness of the service as well as by maintaining a transmission rate at a predetermined ratio among users of different service classes to relatively keep QoS among service classes.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: August 8, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Hidetoshi Kayama, Narumi Umeda