Patents by Inventor Harumi Kokaji

Harumi Kokaji 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: 6643319
    Abstract: A wireless network communication system and method in which the wireless channel can be determined by selecting a vacant pseudonoise (PN) or spreading code. When communication is started, in order to judge whether a PN code is being employed by another communication group, the degree of correlation between the received signal converted to an intermediate frequency or a base-band frequency by a transceiver and a reference pseudonoise code signal is detected using a correlation circuit within a correlation detector. There is a channel controller which controls the PN code used by the communication terminal which receives an output of the correlation detector which correlates a received channel signal with a reference PN code generated by the PN code generator. If the correlation output signal is not smaller than a threshold value, it is determined that the PN code is to be employed.
    Type: Grant
    Filed: October 20, 1995
    Date of Patent: November 4, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Masamitsu Suzuki, Harumi Kokaji, Satoshi Takahashi, Yoshikatsu Nakagawa
  • Patent number: 6400752
    Abstract: A wireless network communication system and method in which the wireless channel can be determined by selecting a vacant pseudonoise (PN) or spreading code. When communication is started, in order to judge whether a PN code is being employed by another communication group, the degree of correlation between the received signal converted to an intermediate frequency or a base-band frequency by a transceiver and a reference pseudonoise code signal is detected using a correlation circuit within a correlation detector. There is a channel controller which controls the PN code used by the communication terminal which receives an output of the correlation detector which correlates a received channel signal with a reference PN code generated by the PN code generator. If the correlation output signal is not smaller than a threshold value, it is determined that the PN code is to be employed.
    Type: Grant
    Filed: October 29, 1998
    Date of Patent: June 4, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Masamitsu Suzuki, Harumi Kokaji, Satoshi Takahashi, Yoshikatsu Nakagawa
  • Patent number: 5745483
    Abstract: A wireless computer network communication system for use in an environment in which plural groups can perform network communication at the same time. A channel controller receives a requirement of starting network communication from a computer, controls a wireless channel sensor, and detects a received signal. The wireless channel detector detects which wireless channel is employed by one or more other networks and the channel controller determines the wireless channel to be employed by its own group and also controls the transceiver. The computer starts the network communication through a network controller. The network controller controls the transceiver for transmitting and receiving data by use of the wireless channel, and the same further controls the transmitting/receiving of the requirements and the data from the computer.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: April 28, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshikatsu Nakagawa, Masamitsu Suzuki, Satoshi Takahashi, Harumi Kokaji
  • Patent number: 5610938
    Abstract: A clock rate modulation spread spectrum (CRM-SS) communication system is provided in which a bit error rate on a receiver side is minimized by controlling at least one of parameters defining a phase error. The CRM-SS communication system uses a delay locked loop comprising an n.DELTA.-type delay locked loop, where 0<n.ltoreq.2. A sum of a plurality of phase errors generated by different causes are calculated. A receiver and/or transmitter is controlled by varying one of parameters including a loop gain K and a linear region n.DELTA. of the phase comparison characteristic of the delay locked loop, a modulation index .beta., a transmission rate fm, a transmission power P and a chip width .DELTA., in accordance with the sum calculated by the calculating means so that a bit error rate in the receiver is minimized.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: March 11, 1997
    Assignee: Ricoh Company, Ltd.
    Inventor: Harumi Kokaji