Patents by Inventor Chung-Zin Liu

Chung-Zin Liu 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: 6061337
    Abstract: A system and method for measuring the approximate distance and direction of a mobile unit from a plurality of cells in order to determine whether and how to handoff the mobile unit and which cell may be the best serving cell. The CDMA timing system is used to provide an estimate of the subscriber's location to be determined by a CDMA base station. A distance calculation is made by the serving cell site sending a request for signal strength message to a mobile unit. The mobile unit measures pilot signal strength and a time offset from the expected time of such pilot signals. The signal strength and time offsets are returned to the cell site. a processor in the system can then determine if a handoff is really desirable, and with which of the cell sites is the best serving all for the mobile unit the mobile unit with a high degree of confidence that the call will be maintained.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: May 9, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: Jeffrey Ross Light, Chung-Zin Liu, Charles Varvaro
  • Patent number: 6002679
    Abstract: A wireless telecommunications system is disclosed that is capable of providing both public wireless service and virtual private network service on existing IS-95 CDMA facilities without changes to the air interface, the hardware design or the protocols for interacting with home location registers. An illustrative embodiment of the present invention comprises: broadcasting from a radio a first SID/NID signal and a FOR.sub.-- NID.sub.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: December 14, 1999
    Assignee: Lucent Technologies Inc.
    Inventors: Chung-Zin Liu, Kenneth Wayne Strom
  • Patent number: 5949770
    Abstract: A method for operating a wireless telecommunications system that is capable of providing both public wireless service and virtual private network service on existing IS-95 CDMA facilities without changes to the air interface, the hardware design or the protocols for interacting with home location registers.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: September 7, 1999
    Assignee: Lucent Technologies Inc.
    Inventors: Chung-Zin Liu, Kenneth Wayne Strom
  • Patent number: 5943332
    Abstract: A wireless telecommunications system that is capable of providing multiple virtual wireless networks (e.g., a public network and/or one or more private networks) from a single IS-95 compliant CDMA radio without changing the air interface or modifying existing hardware designs. Includes the steps of broadcasting from a radio a first SID/NID signal and a FOR.sub.-- NID.sub.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: August 24, 1999
    Assignee: Lucent Technologies Inc.
    Inventors: Chung-Zin Liu, Kenneth Wayne Strom
  • Patent number: 5905953
    Abstract: A wireless telecommunications system is capable of providing both public wireless service and private network service on existing IS-95 CDMA facilities without changes to the air interface or the hardware design.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: May 18, 1999
    Assignee: Lucent Technologies Inc.
    Inventors: Chung-Zin Liu, Kenneth Wayne Strom