Patents by Inventor Ichiro Okajima

Ichiro Okajima 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: 7496084
    Abstract: A mobile node having two or more interfaces, a control method of the mobile node, and a mobile node control program are disclosed. The mobile node includes a generating unit to generate control information for each interface, an information providing unit for providing the control information provided by each interface to an upper layer, and a routing controlling unit to perform at least one of determining connectivity, and updating a routing based on the provided control information.
    Type: Grant
    Filed: June 30, 2005
    Date of Patent: February 24, 2009
    Assignee: NTT DoCoMo, Inc.
    Inventors: Masahiro Inoue, Koji Omae, Ichiro Okajima, Narumi Umeda
  • Patent number: 7496083
    Abstract: Provided is a mobility management node capable of forming a paging area, without need for management of a migration history at a mobile node and for notification of a migration history from a mobile node to a network. In mobility management node (MAP) 1, mobility manager 66 lets binding cache 68 store a home address and a c/o address of each mobile node (MN) in correlation with each other. Migration history storage 70 stores a transition frequency of the c/o address stored in binding cache 68 in correlation with prefixes before and after transition. Migration history storage 70 defines paging area information by a set of prefixes included in combinations containing common prefixes, out of combinations of prefixes before and after transition with each of which a transition frequency over a predetermined reference value is correlated. Paging controller 72 notifies the MN of this paging area information.
    Type: Grant
    Filed: December 24, 2003
    Date of Patent: February 24, 2009
    Assignee: NT DoCoMo, Inc.
    Inventors: Koji Omae, Masahiro Inoue, Ichiro Okajima, Narumi Umeda
  • Patent number: 7492738
    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: Grant
    Filed: July 2, 2004
    Date of Patent: February 17, 2009
    Assignee: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Hideaki Takahashi, Ichiro Okajima, Narumi Umeda
  • Patent number: 7483713
    Abstract: A base station is disclosed. The base station includes: a service area status determination unit configured to determine status of a service area of the base station based on received signals from mobile stations; a total transmission power determination unit configured to determine status of total transmission power of the base station based on total transmission power of surrounding base stations; a transmission power determination unit configured to determine transmission power of a common control channel of the base station based on the status of the service area and the status of the total transmission power; and a transmission power setting unit configured to set the transmission power determined by the transmission power determination unit.
    Type: Grant
    Filed: November 2, 2005
    Date of Patent: January 27, 2009
    Assignee: NTT DoCoMo, Inc.
    Inventors: Shinichi Mori, Ichiro Okajima, Narumi Umeda
  • Patent number: 7433965
    Abstract: A packet transmission system is provided to achieve a higher throughput in downlink packet transmission to a mobile node. When there is a packet call directed to the mobile node, a transmission node in a network in this packet transmission system retrieves information as to a connection point of the mobile node from a distribution location information holder of a home agent. Packets are inputted to a packet distributor situated at the logical location designated by the retrieved connection point information. The packets are then distributed by the packet distributor to radio transmission devices, and are transmitted at once.
    Type: Grant
    Filed: March 11, 2003
    Date of Patent: October 7, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hiroyuki Kawai, Ichiro Okajima, Narumi Umeda
  • Publication number: 20080146244
    Abstract: A mobile node having two or more interfaces, a control method of the mobile node, and a mobile node control program are disclosed. The mobile node includes a generating unit to generate control information for each interface, an information providing unit for providing the control information provided by each interface to an upper layer, and a routing controlling unit to perform at least one of determining connectivity, and updating a routing based on the provided control information.
    Type: Application
    Filed: January 28, 2008
    Publication date: June 19, 2008
    Applicant: NTT DoCoMo, Inc.
    Inventors: Masahiro INOUE, Koji Omae, Ichiro Okajima, Narumi Umeda
  • Patent number: 7362729
    Abstract: In a state I, a link layer of a mobile host is connected to an access router and a default router is set to the access router such that data packets (P1) and (P2) reach the access router and are routed to a correspondent host. In states II and III, data packets (P3) to (P8) are not transmitted but are buffered. When the mobile host switches the default router from the access router to an access router upon reception of a router advertisement from the access router, processing moves to a state IV and the buffered data packets (P3) to (P8) are transmitted. Since the link layer of the mobile host is connected to the access router and the default router is set to the access router, the data packets (P3) to (P8) reach the access router and are routed to the correspondent host.
    Type: Grant
    Filed: March 13, 2003
    Date of Patent: April 22, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Hideaki Takahashi, Ichiro Okajima, Narumi Umeda
  • Patent number: 7349364
    Abstract: When a mobile node MN moves from an access router AR3 to another access router AR4, it sends a multi-binding on request to a mobility agent MA1 and then moves ({circle around (1)}). Receiving the multi-binding on request, the mobility agent MA1 voluntarily configures prospective CoA's (probable CoA's) The probable CoA's are added as forwarding addresses while an M bit is set on in an register of the mobile node MN on a binding cache ({circle around (2)}). When the mobility agent MA1 receives a capsuled packet addressed to the mobile node MN thereafter, it tunnel-forwards the packet to CoA3, probable CoA2, and probable CoA4 according to the binding cache ({circle around (3)}).
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: March 25, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Ichiro Okajima, Narumi Umeda
  • Patent number: 7342932
    Abstract: A packet transmission system includes a home agent providing a home link and a home address to a mobile node, one or more access routers, each providing a foreign link and a c/o address to the mobile node, and one or more mobility support routers that relay a packet to the destination between the mobile node and the home agent or a counterpart correspondent node. When the mobile node moves into a new foreign link, the corresponding access router transmits a registration request to the home agent and/or the correspondent node. When acquiring a registration request on the way to the destination, each mobility support router stores an entry having the home address of the mobile node and the c/o address contained in the registration request, and produces and transmits a new registration request updating the c/o address to its own address.
    Type: Grant
    Filed: August 12, 2002
    Date of Patent: March 11, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Patent number: 7330449
    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: Grant
    Filed: December 18, 2003
    Date of Patent: February 12, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Hideaki Takahashi, Koji Omae, Masahiro Inoue, Ichiro Okajima, Narumi Umeda
  • Patent number: 7321382
    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: Grant
    Filed: June 30, 2004
    Date of Patent: January 22, 2008
    Assignee: NTT DoCoMo, Inc.
    Inventors: Ichiro Okajima, Narumi Umeda
  • Patent number: 7301948
    Abstract: A configuration comprises a destination address extracting/rewriting device 4 for extracting a destination address of a packet; a common-route packet extracting device 8 for extracting two or more packets having a common route at least in part of routes to their respective terminals from a plurality of packets, based on their extracted destination addresses; an aggregate packet creating device 9 for aggregating the plurality of packets having the common route at least in part of the routes to create an aggregate packet including information of each of the packets; a destination address giving device 10 for giving the aggregate packet a destination address so that the destination address of the aggregate packet is an address of an adjacent node on the common route; and an aggregate packet routing device 11 for routing the aggregate packet, based on the destination address.
    Type: Grant
    Filed: June 28, 2002
    Date of Patent: November 27, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Koji Omae, Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Patent number: 7224954
    Abstract: A communication method used when a mobile station receives a signal from a base station in a mobile communication system is provided. The method includes the steps of: deciding one or a plurality of mobile stations which can communicate with the mobile station via a predetermined wireless network and which can receive a signal from the base station; the one or a plurality of mobile stations sending a signal destined for the mobile station received from the base station to the mobile station via the predetermined wireless network; and the mobile station synthesizing a signal received from the base station and the signal destined for the mobile station received from the one or a plurality of mobile stations.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: May 29, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Ichiro Okajima, Yasushi Yamao
  • Publication number: 20070104156
    Abstract: A controller apparatus, when it receives packets addressed to a mobile terminal, implements paging control in which it transmits a paging notification packet to a paging area of the mobile terminal, so as to obtain location information on the mobile terminal and to determine a forwarding destination of the packets. The controller apparatus includes a paging area forming unit having a plurality of algorithms for forming the paging area. The paging area forming unit is configured to form the paging area of the mobile terminal by an algorithm specified by the mobile terminal.
    Type: Application
    Filed: June 18, 2004
    Publication date: May 10, 2007
    Applicant: NTT DoCoMo, Inc
    Inventors: Masahiro Inoue, Ichiro Okajima, Narumi Umeda
  • Patent number: 7171218
    Abstract: A mobile unit capable of communication using a plurality of communication subsystems including a usability determination section to determine usability of the plurality of communication subsystems at the current location of the mobile unit. The mobile unit also includes a communication subsystem selection section for selecting a communication subsystem whereby the current location of the mobile unit can be measured with highest accuracy. A mobile telephone network communication section in the mobile device then measures the current location of the mobile unit and transmits the result of determination of usability, together with information indicating the current location, to an information provision server. Then, the mobile unit is able to look up the result of determination of usability from a plurality of mobile units that is stored in the information provision server.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: January 30, 2007
    Assignee: NTT DoCoMo, Inc.
    Inventors: Takehiro Ikeda, Koji Omae, Ichiro Okajima
  • Patent number: 7139561
    Abstract: A mobile communication system can implement broadcasting control that generates broadcast information autonomously in a distributed manner, thereby obviating the need for an RNC (Radio Network Controller). Each base station has an IP address and a base station multicast address. Each base station sends its own system information to all base stations using the multicast address. Each base station generates its broadcast information from its own system information and the system information received from other base stations. Thus, it can generate the broadcast information autonomously in a distributed manner without using the RNC.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: November 21, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Patent number: 7110752
    Abstract: A radio communication station and method of communications between two radio stations, uses information about the radio communication methods each radio station is equipped to use, such that software used to reconfigure a station is exchanged mutually between the two radio stations by conveying the software according to a predetermined first radio communication method. The radio communication method is suitable for a communication application to be conveyed after the application is selected, where at least one of the two radio stations is equipped with the application as the second radio communication method. Software is transmitted to the radio station that is not equipped with the second radio communication method so it can perform the requisite processing.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: September 19, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventor: Ichiro Okajima
  • Patent number: 7072655
    Abstract: The present invention improves receiving quality compared to the prior art even if instantaneous control of transmission power is not executed. A mobile station MS#0 measures signal level received from surrounding base stations and determines to which base stations it is to be connected in order to satisfy a desired downlink receiving quality (step S1). The mobile station MS#0 notifies a radio network control station RNC of the desired based stations to which the mobile station is to be connected (step S2). Upon receiving the notification from the mobile station MS#0, the radio network control station RNC duplicates a downlink transmitted signal for the mobile station MS#0, if any, and transmits it to the selected base stations (step S3). The mobile station MS#0 receives signals transmitted by the base stations (step S4) and synthesizes these signals (step 5), thereby satisfying the desired downlink receiving quality.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: July 4, 2006
    Assignee: NTT DoCoMo, Inc.
    Inventors: Takehiro Ikeda, Ichiro Okajima, Narumi Umeda
  • Publication number: 20060121907
    Abstract: A base station and a scrambling code setting method of automatically setting up a scrambling code for the base station to use are offered. The base station includes: a scrambling code setting unit for setting up a base station identifier and a provisional downlink scrambling code that is provisionally assigned; and a transmitting unit for spectrum-spreading the base station identifier by the provisional scrambling code, and for transmitting the base station identifier; wherein the scrambling code setting unit assigns a lasting downlink scrambling code based on a report concerning reception of the base station identifier.
    Type: Application
    Filed: November 10, 2005
    Publication date: June 8, 2006
    Applicant: NTT DoCoMo, Inc.
    Inventors: Shinichi Mori, Ichiro Okajima, Narumi Umeda
  • Publication number: 20060111137
    Abstract: A base station is disclosed. The base station includes: a service area status determination unit configured to determine status of a service area of the base station based on received signals from mobile stations; a total transmission power determination unit configured to determine status of total transmission power of the base station based on total transmission power of surrounding base stations; a transmission power determination unit configured to determine transmission power of a common control channel of the base station based on the status of the service area and the status of the total transmission power; and a transmission power setting unit configured to set the transmission power determined by the transmission power determination unit.
    Type: Application
    Filed: November 2, 2005
    Publication date: May 25, 2006
    Applicant: NTT DoCoMo, Inc.
    Inventors: Shinichi Mori, Ichiro Okajima, Narumi Umeda