Patents by Inventor Narumi Umeda

Narumi Umeda 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: 6909905
    Abstract: A mobile communication control system, which includes at least one mobile station and at least one base station, includes first through third parts. The first part measures traffic of radio channels in one or both of the above-mentioned at least one mobile station and the above-mentioned at least one base station. The second part measures a communications quality of radio channels in use. The third part determines a transmit power on a transmitting side and an information transmission bit rate on the basis of the traffic of the radio channels in use and information as to whether the transmit power on the transmitting side has reached a maximum transmit power.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: June 21, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Narumi Umeda, Yasushi Yamao, Lan Chen
  • Patent number: 6895216
    Abstract: The method of invention provides a multicast service from an information delivery apparatus to wireless terminals through wireless routes. The method includes the step of transmitting, from the information delivery apparatus, a plurality of sets of multicast information, wherein these sets are identical to each other as to contents thereof but differ in transmission conditions. The method further includes the step of receiving, at any given one of the wireless terminals, one of the sets of multicast information being transmitted under one of the differing transmission conditions.
    Type: Grant
    Filed: May 3, 2001
    Date of Patent: May 17, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hijin Sato, Narumi Umeda, Yasushi Yamao
  • Publication number: 20050099973
    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: Application
    Filed: November 5, 2004
    Publication date: May 12, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Heng Qiu, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20050099972
    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: Application
    Filed: November 5, 2004
    Publication date: May 12, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masayuki Motegi, Takeshi Yamashita, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 6885865
    Abstract: The mobile station visiting a location registration area at the present time plans to move to another location registration area at a future time. The mobile station sends the moving schedule information to the location management agent in a prescribed format to notify it of the scheduled destination. Receiving the moving schedule information, the location management agent learns the location registration area corresponding to the scheduled destination among the plurality of location registration areas. The location management agent sets a moving schedule flag in the location registration database in accordance with the moving schedule information with that format, which is received from the mobile station, and makes an additional registration of the moving time and the destination location registration area. Then, at the future time, it updates the location registration database, thereby making a new location registration.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: April 26, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Patent number: 6882845
    Abstract: An autonomous zone forming method of autonomously forming a zone which is a service area of a base station in a wireless communication system having the base station is provided. In the method, it is detected that a zone is newly formed around the base station, and a zone which is the service area of the base station is autonomously changed according to a newly formed zone. When determining the zone, receive quality of a signal received from a surrounding base station is used. In addition, a congestion state of a surrounding base station of the base station is detected, and a zone which is the service area of the base station is enlarged to the direction of the surrounding base station according to the congestion state.
    Type: Grant
    Filed: February 2, 2001
    Date of Patent: April 19, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hijin Sato, Narumi Umeda, Yasushi Yamao
  • Patent number: 6871071
    Abstract: In handover control methods and systems which switch a radio base station serving as a communicating counterpart of a mobile station, the present invention provides a handover control method and a system thereof wherein a detection is made when a communication while a predetermined minimum bandwidth secured is not possible at any mobile station communicating with the radio base station and upon the detection the communicating counterpart of the mobile station that communicates with the radio base station mentioned above is switched from the radio base station to other radio base stations.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: March 22, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Toshiaki Takao, Hijin Sato, Narumi Umeda
  • Publication number: 20050041607
    Abstract: A mobile node (MN) transmits a (4) echo request to the effect that the source address is set to be a new care of address (nCoA) right after transmitting a (3) binding update (BU) for a home agent (HA). The nAR having received the (4) echo request intends to transmit an echo reply to the nCoA being the source address of the echo request. However, at this time, since an entry regarding the nCoA does not exist in a neighbor cache of the nAR, the nAR transmits (5) neighbor solicitation (NS) to the MN, and generates a neighbor cache entry of the nCoA. After this, at the time when a binding acknowledgment (BA) has arrived at the nAR, since the entry of the nCoA exists, the (8) BA and data packets (9) to (11) arriving at the nAR following the (8) BA are transferred to the MN without buffering in the nAR, corresponding to the entry of the nCoA generated at the time of transmission of the (7) echo reply.
    Type: Application
    Filed: July 2, 2004
    Publication date: February 24, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Hideaki Takahashi, Ichiro Okajima, Narumi Umeda
  • Publication number: 20050037798
    Abstract: In mobile communication system 100 according to the present invention, mobile station 1 is camped on cell C10 established by base station B10. In the cell C10, there exist indoor cells C11-C13 and outdoor cells C21, C22 as neighboring cells. Mobile station 1 measures received levels of cells C10-C13, C21, C22 and determines cell types of the respective cells, i.e., whether each cell is an indoor cell or not, based on broadcast information M1. Mobile station 1 selects a cell as a reselection target on the basis of the received levels and cell types.
    Type: Application
    Filed: October 17, 2003
    Publication date: February 17, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Takeshi Yamashita, Hideo Matsuki, Jyunichirou Hagiwara, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20050030965
    Abstract: A wireless packet communications apparatus and method are disclosed that enable enhancing of the overall system capacity by reducing, at the time of transmitting a multiple number of packets, redundant waiting time periods and appending of redundant information items.
    Type: Application
    Filed: July 29, 2004
    Publication date: February 10, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Hidenori Aoki, Junichiro Hagiwara, Narumi Umeda
  • Publication number: 20050030918
    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: Application
    Filed: July 1, 2004
    Publication date: February 10, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masayuki Motegi, Hideki Tobe, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20050027847
    Abstract: An apparatus is adapted to configure a virtual communication device that includes communication devices accessible to the apparatus. A signal interface receives from a calling communication device information data including first and second content parts, and an information separating unit separates the first and second content parts of the information data. A DMF unit identifies communication attributes of the communication devices accessible thereto and identifies the communication devices capable of processing information corresponding to at least one of the first and second content parts.
    Type: Application
    Filed: June 30, 2004
    Publication date: February 3, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Ichiro Okajima, Narumi Umeda
  • Publication number: 20050025056
    Abstract: In a packet communications method of performing packet communications between a mobile station and a base station, the base station manages an amount of packets stored in a transmission buffer of the mobile station. The mobile station notifies a changed result of an amount of packets stored in the transmission buffer of the mobile station, when the amount of packets stored in the transmission buffer of the mobile station changes. The base station changes a managed amount in accordance with the changed result notified from the mobile station.
    Type: Application
    Filed: May 14, 2004
    Publication date: February 3, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Lan Chen, Daisuke Kitazawa, Hidetoshi Kayama, Narumi Umeda
  • Publication number: 20050007995
    Abstract: In a packet communications system, a control apparatus implements routing control of a received packet directed for the mobile terminal. The mobile terminal includes a plurality of network interface cards; a communication manager configured to select at least one network interface card among from the plurality of network interface cards, in accordance with information regarding the network interface card; and an upper layer manager configured to receive the packet transmitted from the control apparatus, with using a selected network interface card.
    Type: Application
    Filed: July 9, 2004
    Publication date: January 13, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masahiro Inoue, Ichiro Okajima, Narumi Umeda
  • Publication number: 20050003836
    Abstract: A paging agent 30 according to the present invention receives a paging request packet from a mobile node, and then determines a paging area, in response to the packet. The paging agent 30 notifies the mobile node of the determined paging area and controls this paging area. When the paging agent 30 receives a data packet directed to the mobile node in a paging control mode, it holds the packet in a buffer 371 and starts forwarding the data packet thus held, as triggered by reception of a paging notification confirmation packet from the mobile node.
    Type: Application
    Filed: June 4, 2004
    Publication date: January 6, 2005
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masahiro Inoue, Koji Omae, Ichiro Okajima, Narumi Umeda
  • Patent number: 6839559
    Abstract: A retransmission control method is provided. In the method, all base stations perform error judgment for a signal sent from a mobile station 1. Then, first and second base stations send results of error judgment to a third base station which is a communication partner of the mobile station 1. The third base station sends NACK for requesting retransmission to the mobile station 1 only when every result of error judgment of the first and second base stations indicates that there is an error.
    Type: Grant
    Filed: November 14, 2001
    Date of Patent: January 4, 2005
    Assignee: NTT DoCoMo, Inc.
    Inventors: Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Publication number: 20040258008
    Abstract: A network system implements paging control in which the control apparatus, upon receiving a packet destined for a mobile terminal, transmits a paging notification packet to a paging area of the mobile terminal, so as to obtain location information of the mobile terminal and to determine a transfer destination of a received packet. The control apparatus is configured to transmit the paging notification packet to a plurality of router devices included in the paging area. Each of the plurality of router devices is configured to transmit a received paging notification packet to a plurality of access points by multicasting. Each of the plurality of access points is configured to transmit a received paging notification packet to the mobile terminal through a link connection by multicasting, when it is judged that an IP address in the paging notification packet is a predetermined IP address.
    Type: Application
    Filed: June 21, 2004
    Publication date: December 23, 2004
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masahiro Inoue, Ichiro Okajima, Narumi Umeda
  • Publication number: 20040254980
    Abstract: An object is to implement smooth execution of management of location information of a mobile station according to states of the mobile station varying with time. Based on a notification of transition into a sleep state from the mobile station, transmitted upon a timeout of a sleep state determination timer with neither packet transmission nor reception at the mobile station, it is determined that the mobile station has moved into the sleep state, and control processing in the link layer is executed (S12) (the control processing in the link layer carried out when the mobile station moves between cells).
    Type: Application
    Filed: June 30, 2004
    Publication date: December 16, 2004
    Inventors: Masayuki Motegi, Hidetoshi Kayama, Narumi Umeda
  • Patent number: 6831904
    Abstract: A mobile communication system includes a line control station, and a plurality of base stations belonging to a plurality of clusters so that each of the clusters includes a plurality of base stations. Each of the clusters includes a cluster control station which is connected to the line control station via a line and controls the base stations within the cluster to which the cluster control station belongs. In addition, each of the base stations within one cluster is connected to other base stations within the one cluster and/or the cluster control station within the one cluster via lines, so that each of the base stations within the one cluster is directly or indirectly connected to the cluster control station within the one cluster.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: December 14, 2004
    Assignee: NTT DoCoMo, Inc.
    Inventors: Yasushi Yamao, Hirohito Suda, Narumi Umeda
  • Publication number: 20040218573
    Abstract: An object of the present invention is to decrease a care-of address update duration in switching of a link used for connection to an IP network by a mobile node (MN). MN acquires a list of access routers (ARs) existing on neighboring links to the link used for connection by the mobile node and creates a list of care-of addresses (CoAs) corresponding to the respective ARs entered in the list, each CoA being used as a destination of MN at a link on which an AR corresponding thereto exists. After the change of the connected link, MN acquires a data link layer address of AR existing on the link after the change and detects a default router on the basis of the address with reference to the access node list. Furthermore, MN detects a CoA with a network prefix corresponding with a subnet prefix of the default router, as a primary CoA and requests MAP to register a binding between the primary CoA and HoA.
    Type: Application
    Filed: December 18, 2003
    Publication date: November 4, 2004
    Applicant: NTT DoCoMo, Inc
    Inventors: Hideaki Takahashi, Koji Omae, Masahiro Inoue, Ichiro Okajima, Narumi Umeda