Patents by Inventor Takao Harakawa

Takao Harakawa 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: 5652752
    Abstract: In a mobile radio communication system employing a time-division multiple transmission scheme, having a plurality of base stations and a plurality of personal stations, an arbitrary base station, when detecting a pilot signal transmitted from any master base station in the mobile radio communication system, acts as a slave base station which does not transmit its pilot signal but transmits and receives a common control signal to and from a personal station utilizing a frequency channel occupied by the pilot signal. On the other hand, when not receiving the pilot signal, the base station searches for an available frequency channel, and acts as a master base station which transmits its pilot signal on the available frequency channel to occupy the frequency channel, and transmits and receives the common control signal to and from a personal station on that frequency channel.
    Type: Grant
    Filed: March 20, 1995
    Date of Patent: July 29, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Toshiro Suzuki, Arata Nakagoshi, Takao Harakawa, Izumi Horikawa, Takakuni Kuki
  • Patent number: 5586122
    Abstract: In a time division multiple access mobile wireless telecommunication system, a base station has a plurality of frequencies with their priority order previously registered in a memory, selects, upon starting the operation, the frequency having the highest priority from frequencies not used by other wireless telecommunication systems, and initiates communications at the selected frequency. The base station also transmits a pilot signal representative of the priority for using the selected frequency in order to prevent other wireless telecommunication system from interrupting to use the frequency.
    Type: Grant
    Filed: December 7, 1994
    Date of Patent: December 17, 1996
    Assignees: Hitachi, Ltd., Matsushita Electric Industrial Co., Ltd.
    Inventors: Toshiro Suzuki, Takao Harakawa, Kazuhito Ishida, Izumi Horikawa