Patents by Inventor Kenzaburo Fujishima

Kenzaburo Fujishima 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: 7236879
    Abstract: In the present invention, even if a mobile terminal is close to a base station, the position of the mobile terminal is measured accurately. The disclosed method for calculating the position of a mobile terminal comprises: measuring the differences between the propagation distances of the signals on the channels between a plurality of base stations and the mobile terminal; determining if the mobile terminal is close to a base station; calculating the position of the mobile terminal by a common formula if it is determined that the mobile terminal is not in close proximity to any of the base stations; calculating the position of the mobile terminal in close proximity to a base station if it is determined that the mobile terminal is in close proximity to one of the base stations; and outputting the position of the mobile terminal calculated through either of the routines for calculating the mobile terminal position.
    Type: Grant
    Filed: January 14, 2004
    Date of Patent: June 26, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiko Tsunehara, Kenzaburo Fujishima
  • Publication number: 20070115867
    Abstract: This invention provides a controller of multiplex number in spatial domain that collects from a plurality of radio communication apparatuses the number of terminals connected thereto and the multiplex number in spatial domain, determines the ratio of (the number of terminals connected thereto)/(the multiplex number in spatial domain) for each radio communication apparatus, and adjusts the multiplex number for each radio communication apparatus so that the above ratio will be equal between or among the radio communication apparatuses. The radio communication apparatuses transmit the number of terminals connected thereto and the multiplex number in spatial domain to the controller of multiplex number in spatial domain.
    Type: Application
    Filed: March 23, 2006
    Publication date: May 24, 2007
    Inventors: Kenzaburo Fujishima, Masanori Taira, Mikio Kuwahara
  • Publication number: 20060217158
    Abstract: A wireless communication which suppresses radio interference between wireless base stations and improves the channel efficiency is implemented. In the wireless communication system including a central base station, a plurality of remote base stations having a direction-variable antenna, and a plurality of mobile stations to communicate with the remote base stations, the central base station performs centralized management of radio-wave beam patterns to be sent to the plurality of mobile stations which will communicate with remote base stations and performs packet scheduling of the mobile stations in such a manner that radio waves sent from the remote base stations will not cause strong interference at the mobile stations.
    Type: Application
    Filed: February 9, 2006
    Publication date: September 28, 2006
    Inventors: Koki Uwano, Masanori Taira, Kenzaburo Fujishima, Mikio Kuwahara
  • Patent number: 7110775
    Abstract: In calculation of a position of a terminal, there arises, when creating a delay profile, a problem to select a transmission code for a sector of a base station to create the delay profile. According to a position of a base station and a bearing of each antenna forming a sector of the base station, a wireless position calculation method selects a transmission code for a sector of a base station to create a delay profile. Under a condition that the number of delay profiles to be created is limited, each delay profile is created in consideration of the antenna bearing. Therefore, the number of base stations at mutually different positions is increased to calculate the position and precision of the position calculation is improved.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: September 19, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Ogino, Kenzaburo Fujishima, Hideya Suzuki
  • Publication number: 20060189353
    Abstract: A base station apparatus is provided for adaptively controlling a maximal accommodation channel number per unit area (for example, the coverage area of a cell or sector) in accordance with a traffic quantity without relying upon detachment of a mobile base station and installation of a repeater. Upon inputting of a plurality of baseband signals of a user channel-multiplexed channel group, linear coupling is performed by a weight which is different per area that outputs it, thereby enabling control of the channel density. Additionally, a per-group available channel number is constantly monitored to control the weight while using threshold judgment for the available channel number as a trigger, thus achieving situation-sensitive prompt handleability.
    Type: Application
    Filed: August 4, 2005
    Publication date: August 24, 2006
    Inventor: Kenzaburo Fujishima
  • Patent number: 7072673
    Abstract: A radio handset includes: a signal receiver for receiving signals from a plurality of radio stations; a reception timing analyzer for analyzing reception timings of signals received by the signal reception means; a radio station selector for selecting radio stations to be used in a position calculation; and a position calculator for calculating a position of a signal reception point by using the reception timings of the signals from the selected radio stations. The radio station selector selects the radio stations to be used in the position calculation in such a manner that when reception timings of signals from two or more of the radio stations cannot be separated from one another, it is decided to exclude a signal from at least one of these radio stations.
    Type: Grant
    Filed: October 22, 2002
    Date of Patent: July 4, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Katsuhiko Tsunehara, Kenzaburo Fujishima, Mikio Kuwahara, Koji Watanabe
  • Patent number: 7013111
    Abstract: The disclosed invention provides a wireless communications terminal apparatus that calculates its accurate position, eliminating the influence of a repeater on the calculation without using complicated processing. The terminal apparatus receives signals transmitted from a plurality of radio stations and calculates its position, using the received signals. The terminal apparatus comprises repeater detection means for detecting a signal from a repeater which transmits signals that are generated on the basis of signals transmitted from one of the radio stations and indistinguishable from the signals transmitted from that radio station from among the received signals and position calculation means for calculating its position. When the repeater detection means has detected a signal from a repeater, the position calculation means ignores the detected signal from the repeater and calculates the terminal position, using the received signals from other radio stations.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: March 14, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Kenichi Mizugaki, Atsushi Ogino, Kenzaburo Fujishima
  • Patent number: 6990345
    Abstract: In a method for locating a position of a terminal with use of weak signals, a combined weight to be used to separate a path from others through correlation calculation is obtained from a plurality of delay profiles measured in course of time. The obtained weight is used to combine the delay profiles and a path detection is carried out on the combined delay profiles.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: January 24, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima
  • Publication number: 20060002287
    Abstract: To provide a wireless base station comprising an array antenna which transmits packets to terminals, a packet scheduler which determines transmission sequence of the packets, a modulator which generates modulated signals based on the packets, and a beam former for transmission signal which multiplies the packets with array weights for transmission signal and outputs the transmission signal to the array antenna the beam former for transmission signal comprises a memory which stores the array weights for transmission signal associated with the terminals' IDs. The beam former for transmission signal receives the IDs of selected terminals from the packet scheduler, refers to the memory, and selects the array weights for transmission signal by the IDs of the terminals.
    Type: Application
    Filed: February 25, 2005
    Publication date: January 5, 2006
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima, Masanori Taira, Koji Meguro, Toru Okamoto
  • Publication number: 20060002421
    Abstract: To reduce power consumption of a mobile station, this invention provides a wireless communication method for communicating between a base station and a plurality of terminals using a plurality of channels, the channels being slots obtained by dividing frequency-divided carriers by time, in which the base station allocates a set of the channels which is composed of a plurality of neighboring carriers and/or a plurality of successive slots for the each terminal, and the base station allocates at least one of the channels included in the channel sets for packet transmission the terminals.
    Type: Application
    Filed: February 25, 2005
    Publication date: January 5, 2006
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima, Masanori Taira
  • Patent number: 6950661
    Abstract: A location calculation method for calculating, by using propagation delay time of signals received from wireless transmitters, a location of a reception point of the signals to thereby reduce errors in the distance measurement due to an erroneous detection of a path of a received signal includes first step of measuring reception timing of signals received from the wireless transmitters, second step of estimating, according to results of measurement of the reception timing obtained by the first step, an erroneous result of measurement, and third step of removing the results of measurement estimated as the erroneous results by the second step from the results of measurement of the reception timing obtained by the first step, and thereby calculating the location of the reception point.
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: September 27, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Koji Watanabe, Mikio Kuwahara, Katsuhiko Tsunehara, Kenzaburo Fujishima
  • Publication number: 20050197162
    Abstract: A radio communication apparatus enhances cell throughput by adaptive selection of spatially multiplexed channels in consideration of interferences in a local cell and reducing load for calculation of array weights by storing them in advance as fixed values and outputting fixed beams. To reduce the calculation load for the adaptive selection of spatially multiplexed channels that takes interferences within the local cell into consideration, the radio communication apparatus adopts a packet scheduling method that selects a combination of fixed beams and determines the number of spatially multiplexed channels, based on the fixed beams for mobile apparatuses with packets waiting to be transmitted and pre-calculated correlative quantities of inter-beam interferences between these fixed beams.
    Type: Application
    Filed: February 4, 2005
    Publication date: September 8, 2005
    Inventors: Kenzaburo Fujishima, Mikio Kuwahara, Masanori Taira, Koji Meguro, Toru Okamoto
  • Patent number: 6889051
    Abstract: An offset measuring method according to the present invention accurately measures a transmitting time offset of a base station. The offset measuring method for receiving signals from the radio base station and measuring the transmitting time offset of the radio base station includes the steps of calculating estimated values of transmitting time offset based on signals received at a plurality of observation points and selecting a minimum from the estimated offsets to determine the selected minimum value as transmitting time offset of the radio base station.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: May 3, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Ogino, Mikio Kuwahara, Tomoaki Ishifuji, Kenzaburo Fujishima
  • Publication number: 20040235472
    Abstract: A signal transmission and reception method, and a base station and a mobile terminal therefor are disclosed. In a communication system including a base station and at least a mobile terminal, the transmission of the data signal from the base station to each mobile terminal is controlled in accordance with the manner in which the pilot signal transmitted from the base station to each mobile terminal is received by the mobile terminal. In the signal transmission method, the proper one of a plurality of signal multiplexing schemes is selected based on the control signal received from each mobile terminal, and the transmission signal is multiplexed by the selected signal multiplexing scheme and transmitted to each mobile terminal. The transmission signal includes the data signal and the dedicated pilot signal transmitted to the mobile terminal.
    Type: Application
    Filed: May 18, 2004
    Publication date: November 25, 2004
    Applicants: Hitachi, Ltd., Hitachi Communication Technologies, Ltd.
    Inventors: Kenzaburo Fujishima, Mikio Kuwahara
  • Publication number: 20040203913
    Abstract: In calculation of a position of a terminal, there arises, when creating a delay profile, a problem to select a transmission code for a sector of a base station to create the delay profile. According to a position of a base station and a bearing of each antenna forming a sector of the base station, a wireless position calculation method selects a transmission code for a sector of a base station to create a delay profile. Under a condition that the number of delay profiles to be created is limited, each delay profile is created in consideration of the antenna bearing. Therefore, the number of base stations at mutually different positions is increased to calculate the position and precision of the position calculation is improved.
    Type: Application
    Filed: January 13, 2003
    Publication date: October 14, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Atsushi Ogino, Kenzaburo Fujishima, Hideya Suzuki
  • Publication number: 20040172190
    Abstract: In the present invention, even if a mobile terminal is close to a base station, the position of the mobile terminal is measured accurately. The disclosed method for calculating the position of a mobile terminal comprises: measuring the differences between the propagation distances of the signals on the channels between a plurality of base stations and the mobile terminal; determining if the mobile terminal is close to a base station; calculating the position of the mobile terminal by a common formula if it is determined that the mobile terminal is not in close proximity to any of the base stations; calculating the position of the mobile terminal in close proximity to a base station if it is determined that the mobile terminal is in close proximity to one of the base stations; and outputting the position of the mobile terminal calculated through either of the routines for calculating the mobile terminal position.
    Type: Application
    Filed: January 14, 2004
    Publication date: September 2, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Katsuhiko Tsunehara, Kenzaburo Fujishima
  • Publication number: 20040072566
    Abstract: In a method for locating a position of a terminal with use of weak signals, a combined weight to be used to separate a path from others through correlation calculation is obtained from a plurality of delay profiles measured in course of time. The obtained weight is used to combine the delay profiles and a path detection is carried out on the combined delay profiles.
    Type: Application
    Filed: January 16, 2003
    Publication date: April 15, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima
  • Patent number: 6671649
    Abstract: A position calculation method that calculates the correct position of a terminal even when errors are not distributed symmetrically for positive and negative values, by calculating the position of a terminal using the delay time of received signals. The method calculates a first range that is a difference between a range from the terminal to each of antenna and a range from the terminal to a base antenna, the range being calculated from a wireless signal delay time; calculates a second range that is a difference between a range from an assumed terminal position for calculation to each antenna and a range from the assumed terminal position for calculation to the base antenna; calculates a likelihood of the position of the terminal, repeats these procedures to obtain a point where the likelihood is maximized, and determines an obtained most likely solution as the position of the terminal.
    Type: Grant
    Filed: March 19, 2003
    Date of Patent: December 30, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Tomoaki Ishifuji, Takashi Yano, Kenzaburo Fujishima
  • Publication number: 20030191604
    Abstract: A position calculation method that calculates the correct position of a terminal even when errors are not distributed symmetrically for positive and negative values, by calculating the position of a terminal using the delay time of received signals. The method calculates a first range that is a difference between a range from the terminal to each of antenna and a range from the terminal to a base antenna, the range being calculated from a wireless signal delay time; calculates a second range that is a difference between a range from an assumed terminal position for calculation to each antenna and a range from the assumed terminal position for calculation to the base antenna; calculates a likelihood of the position of the terminal, repeats these procedures to obtain a point where the likelihood is maximized, and determines an obtained most likely solution as the position of the terminal.
    Type: Application
    Filed: March 19, 2003
    Publication date: October 9, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Tomoaki Ishifuji, Takashi Yano, Kenzaburo Fujishima
  • Publication number: 20030162550
    Abstract: The disclosed invention provides a wireless communications terminal apparatus that calculates its accurate position, eliminating the influence of a repeater on the calculation without using complicated processing. The terminal apparatus receives signals transmitted from a plurality of radio stations and calculates its position, using the received signals. The terminal apparatus comprises repeater detection means for detecting a signal from a repeater which transmits signals that are generated on the basis of signals transmitted from one of the radio stations and indistinguishable from the signals transmitted from that radio station from among the received signals and position calculation means for calculating its position. When the repeater detection means has detected a signal from a repeater, the position calculation means ignores the detected signal from the repeater and calculates the terminal position, using the received signals from other radio stations.
    Type: Application
    Filed: July 29, 2002
    Publication date: August 28, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Mikio Kuwahara, Kenichi Mizugaki, Atsushi Ogino, Kenzaburo Fujishima