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).

  • Publication number: 20010027107
    Abstract: A location managing method for managing a location of a mobile station in a mobile wireless packet communication system in which each of communication nodes down to a base station have a hierarchical structure, wherein a route from a communication node positioned at a highest layer of the hierarchical structure to a base station of a cell in which a mobile station is located, is managed as location information of the mobile station, by being distributed to the communication node located at the highest layer of the hierarchical structure and to each of communication nodes in the route to the base station.
    Type: Application
    Filed: December 19, 2000
    Publication date: October 4, 2001
    Applicant: NNT DoCoMo, Inc.
    Inventors: Takuya Shinozaki, Narumi Umeda, Yasushi Yamao
  • Publication number: 20010021246
    Abstract: Terminal management information concerning a plurality of communication terminals of a user is managed. When a call addressed to the user is initiated, one or more terminals that can accept the call is identified by referring to an ability needed for a communication involved in the call and the terminal management information concerning the plurality of communication terminals managed by the step (a). Information involved in the call into items of information to be sent to the above one or more terminals identified by the step (b) and combining items of information from the above one or more terminals identified by the step (b) is separated into information to be sent to one of the plurality of communication terminals that initiates the call. A virtual terminal is formed by the above one or more terminals identified by the step (b) and communicates with the above one of the plurality of communication terminals.
    Type: Application
    Filed: December 26, 2000
    Publication date: September 13, 2001
    Applicant: NTT DoCoMo, Inc
    Inventors: Ichiro Okajima, Narumi Umeda
  • Publication number: 20010017882
    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: Application
    Filed: December 27, 2000
    Publication date: August 30, 2001
    Applicant: NTT DoCoMo, Inc.
    Inventors: Narumi Umeda, Yasushi Yamao, Lan Chen
  • Publication number: 20010018346
    Abstract: A mobile communication system is provided including a plurality of base stations placed in a communication service area and connected to a network, wherein a mobile station communicates with a second station through the plurality of base stations and the network. The mobile communication system determines a virtual base station group, that is, an aggregation of the plurality of base stations communicating with the mobile station, based on a condition of a radio transmission path between the mobile station and each base station, and combines information received by the plurality of base stations that belong to the virtual base station group at a base station included in the virtual base station group, wherein the network connects the plurality of base stations non-hierarchically, wherein the base station transmits combined information to the second station through the network.
    Type: Application
    Filed: December 27, 2000
    Publication date: August 30, 2001
    Applicant: NTT DoCoMo, Inc.
    Inventors: Ichiro Okajima, Narumi Umeda, Yoshifumi Suzuki, Yasushi Yamao
  • Publication number: 20010014092
    Abstract: A packet communication method of performing communication employing a packet having a transmission-source address and destination address, comprises the steps of: making a predetermined number of bits of the transmission-source address and a predetermined number of bits of destination address be fixed addresses; a repeating node for repeating a packet from a transmission-source terminal first converting the fixed address of the transmission-source address of the received packet into an address of an higher-rank station of the repeating node; and the repeating address converting the fixed address of the destination address of the received packet into an address of an higher-rank station of a last repeating node for a destination terminal, and transferring the packet.
    Type: Application
    Filed: December 22, 2000
    Publication date: August 16, 2001
    Applicant: NTT DoCoMo, Inc.
    Inventors: Yoshifumi Suzuki, Takuya Shinozaki, Ichiro Okajima, Narumi Umeda
  • Publication number: 20010014089
    Abstract: A header structure of a packet, which is transferred to a mobile terminal through a packet communication network that includes a plurality of routers inclusive of communication routers configured to communicate with mobile terminals through radio, includes information about conditions of destination mobile terminals for which the packet is destined. This information serves as indication of destination.
    Type: Application
    Filed: December 27, 2000
    Publication date: August 16, 2001
    Applicant: NTT DoCoMo, Inc.
    Inventors: Ichiro Okajima, Narumi Umeda
  • Patent number: 5940385
    Abstract: A multicellular transmission apparatus in a mobile communication network, capable of preventing delay involved in reassembling short packets into fixed length packets (ATM cells), degradation of communication signals due to the delay, and reduction of the transmission efficiency involved in assembling the short packets into the fixed length packets. When low speed information transmitted from a telephone set is converted into short packets by communication data assemblers/disassemblers in a mobile gateway switching center, followed by multiplexing of the short packets into the fixed length packets by fixed length packet assemblers/disassemblers, the short packets sent from a plurality of telephone sets are grouped for each destination node (a particular radio base station, for example) in the network, and are multiplexed into the fixed length packets belonging to the group bound for the destination of the short packets.
    Type: Grant
    Filed: October 22, 1996
    Date of Patent: August 17, 1999
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Yasuhiro Mita, Masami Yabusaki, Narumi Umeda
  • Patent number: 5920817
    Abstract: A mobile communication scheme realizing highly reliable handover and improved service quality. The communication signals containing identical communication data are transmitted simultaneously from the mobile station to more than one base stations at a time of the handover, such that reception signals are composed from the communication signals received by more than one base stations by using the reliability information for the received communication signals. For the packet communication, the identification information for identifying each packet is attached to each packet, and the reliability information for each packet is measured, such that the reception packets can be obtained according to the identification information attached to each packet and the reliability information measured for each packet.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: July 6, 1999
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Narumi Umeda, Takehiro Nakamura, Kouji Ohno, Noriteru Shinagawa
  • Patent number: 5873047
    Abstract: A method for setting up perch channels in a mobile communication by a cellular system, capable of setting up a perch channel and a perch channel list for surrounding base stations at each newly provided base station autonomously. At the newly provided base station, reception levels of signals transmitted by mobile stations to surrounding base stations are measured by scanning uplink control channels corresponding to perch channels, and a perch channel of the newly provided base station and a perch channel list to be signaled by the newly provided base station are autonomously set according to the measured reception levels.
    Type: Grant
    Filed: October 9, 1996
    Date of Patent: February 16, 1999
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Etsuhiro Nakano, Narumi Umeda
  • Patent number: 5873028
    Abstract: A transmission power control scheme for a mobile communication system for suppressing the transmission power to an absolutely necessary minimum level, and increasing the subscriber capacity by reducing an amount of interference. In this scheme, at a time of controlling a transmission power of each radio channel at one of the base station and the mobile station so as to make a difference between a target CIR and a reception CIR of each radio channel at another one of the base station and the mobile station smaller, the target CIR for all radio channels at that another one of the base station and the mobile station are set independently, and/or the target CIR for each radio channel is changed at that another one of the base station and the mobile station, according to a channel quality of each radio channel at either one of the base station and the mobile station.
    Type: Grant
    Filed: October 20, 1995
    Date of Patent: February 16, 1999
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Etsuhiro Nakano, Narumi Umeda, Tomohiro Dohi
  • Patent number: 5838671
    Abstract: A call admission control scheme for a CDMA mobile communication system which can satisfy a given connection quality (blocking probability) while guaranteeing a predetermined communication quality. At each base station, a blocking probability and an outage probability of communication quality at each base station are calculated to adjust a maximum number of simultaneously connectable users at each base station according to the calculated results, and a call admission control is carried out according to the adjusted maximum number of simultaneously connectable users.
    Type: Grant
    Filed: June 18, 1996
    Date of Patent: November 17, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Yoshihiro Ishikawa, Narumi Umeda
  • Patent number: 5740168
    Abstract: A radio link switching scheme in which a communication between the base station and the mobile station is carried out through the radio link given in terms of frames while providing a switching timing information formed by a layer 1 bit data in each frame of the radio link such as a unique word, a flag, a housekeeping bit, and a frame number. Then, the switching timing information in at least one of the frames of the radio link at the base station is changed to indicate a switching of the radio link whenever a need for switching the radio link between the base station and the mobile station arises, and transmitted to the mobile station. At the base station, the radio link is switched at a switching timing which is a prescribed period of time after each frame in which the switching timing information is changed, while at the mobile station the radio link is switched at a switching timing which is a predetermined period of time after each frame in which the changed switching timing information is detected.
    Type: Grant
    Filed: June 12, 1995
    Date of Patent: April 14, 1998
    Assignee: NTT Mobile Communication Network Inc.
    Inventors: Takehiro Nakamura, Narumi Umeda, Akira Hiroike
  • Patent number: 5689503
    Abstract: When data is transferred by using a plurality of time slots, the transferring period is shortened by adopting priority to assign the required number of slots. The base station BS which accepted packet P1 generates a "BUSY" signal and an echo at the final portion of the first time slot TS which begins at time t4. The base station BS, recognizing that there is a packet following the packet P1, generates a "RESERVED" signal at the final portion of the time slot TS which begins at time t5. The mobile station MS-A learns that the first time slot is assigned by recognizing the "BUSY" signal and the echo, and that the second time slot is also assigned by recognizing the "RESERVED" signal. Therefore, the first and second time slots are used successively for fast transferring.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: November 18, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Azusa Wada, Akihiro Maebara, Ichiro Okajima, Katsumi Kobayashi, Noriko Uchida, Shinji Uebayashi, Narumi Umeda
  • Patent number: 5673260
    Abstract: CDMA mobile communication method and system for realizing an autonomous distributed control of radio channel allocation, a synchronization control for a smooth establishment/switching, and a VOX control for a capacity increase are provided. At either one station of each base station and the mobile station, one of a plurality of prescribed short spread codes is selected, and a data sequence to be transmitted is spread by using the selected short spread code and a prescribed long spread code and then transmitted, while at another one station, the data sequence before spreading is reproduced and received by despreading the data sequence from that either one station by using the selected short spread code and the prescribed long spread code.
    Type: Grant
    Filed: October 5, 1995
    Date of Patent: September 30, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Narumi Umeda, Akihiro Higashi, Akira Hiroike, Akira Kaiyama
  • Patent number: 5666655
    Abstract: A mobile communication system using an autonomous distributed type dynamic channel allocation scheme, in which each base station manages allocation priority levels for the available radio channels according to past records of channel use for each radio channel, and updates the allocation priority level of each radio channel by weighting past allocation accept/reject judgement results for each radio channel with weight factors which vary according to time intervals of the past allocation accept/reject judgement results from a current time. The mobile stations can be grouped into N groups according to states of the mobile stations and N sets of allocation priority levels for each radio channel in correspondence to these N groups can be managed at each base station. The thresholds for grouping the mobile stations can be determined according to past records of states of the mobile stations.
    Type: Grant
    Filed: February 2, 1995
    Date of Patent: September 9, 1997
    Assignee: NTT Mobile Communication Network Inc.
    Inventors: Yoshihiro Ishikawa, Narumi Umeda
  • Patent number: 5596516
    Abstract: A code sequence generator having a register for holding n-bit code, and a calculation circuit for performing matrix calculation on the content of the register, and sequentially generating a code sequence by feeding back the calculation results to the register. The matrix which is set in the calculation circuit is changed by selectively reading a matrix from a memory circuit that stores precalculated matrices. This makes it possible to set a desired register state in a short time even if the desired code sequence is very long, and to generate any code sequences without changing the rate of a clock signal.
    Type: Grant
    Filed: April 25, 1995
    Date of Patent: January 21, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Akihiro Higashi, Koji Ohno, Narumi Umeda
  • Patent number: 5581547
    Abstract: Mobile stations randomly set delay amounts for each message to be sent, on the basis of the timing of a symbol received from a base station, and delay transmission signals for time intervals corresponding to the delay amounts. The base station 11 despreads signals received from the mobile stations to extract basic symbol timing for each mobile station and, at the thus extracted timing, takes each despread output into the corresponding demodulator for demodulation.
    Type: Grant
    Filed: October 25, 1994
    Date of Patent: December 3, 1996
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Narumi Umeda, Youichi Douzono, Tadashi Matsumoto
  • Patent number: 5574983
    Abstract: A base station and a mobile station in a mobile communication system capable of reducing interference among mobile stations and increasing a subscriber capacity of the system. The base station has a unit for measuring a measurement value for at least one of a receiving level and an interference ratio level of the mobile station transmission signals, and a unit for producing a mobile station transmission power control data specifying a mobile station transmission power required in adjusting the measurement value to a target level according to a number of base stations simultaneously in communication with the mobile station.
    Type: Grant
    Filed: September 29, 1994
    Date of Patent: November 12, 1996
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Youichi Douzono, Narumi Umeda
  • Patent number: 5568472
    Abstract: In a mobile communication system which uses a code division multiple access (CDMA) scheme for communications between a base station and a plurality of mobile stations, the base station has a transmitting device in which a plurality of information sequences S1 through Sn are respectively spread by multipliers 11 through 1n with a common spreading code from a spreading code generator circuit 10, the spread codes are provided to transmitting timing control circuits 21 through 2n and then added by an adder 30 to perform transmitting timing offset multiplexing and then the spread signals are transmitted to the mobile stations at different transmitting timing. The mobile stations each have a receiving device which receives that one of the transmitted signals which was transmitted at timing predetermined for the mobile station and despreads the received signal with the same spreading code as that used in the transmitting device, thereby reconstructing the original information sequence concerned.
    Type: Grant
    Filed: June 29, 1994
    Date of Patent: October 22, 1996
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Narumi Umeda, Tadashi Matsumoto, Youichi Douzono
  • Patent number: 5566165
    Abstract: A transmission power control method for a CDMA system including the steps of calculating an actual SIR (Signal-to-Interference Ratio) of a desired signal; deciding whether the actual SIR is greater than a predetermined reference SIR which satisfies a predetermined conununication quality; forming a transmission power control bit on the basis of a result of deciding; inserting the transmission power control bit periodically into a forward frame, which steps are performed at the base station, and steps of calculating tentative reverse transmission power in accordance with the transmission power control bit in the forward frame; deciding reverse transmission power such that the reverse transmission power is made equal to the tentative reverse transmission power when the tentative reverse transmission power is less than a predetermined maximum transmission power, but otherwise made equal to the predetermined maximum transmission power; and transmitting a signal from the mobile station to the base station at the re
    Type: Grant
    Filed: May 11, 1995
    Date of Patent: October 15, 1996
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Mamoru Sawahashi, Narumi Umeda, Tomohiro Dohi, Koji Ohno