Patents by Inventor David N. Hoogerwerf

David N. Hoogerwerf 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: 6035188
    Abstract: A method and system for actively and rapidly collecting reference waveforms from a large number of cellular telephones is provided. The reference waveforms are used to generate fingerprints which are used to distinguish between authorized cellular telephones and unauthorized cellular telephones. Initially, the system selects a cellular telephone whose reference waveform is desired. The selected cellular telephone is then sent a polling message such as a page or registration request. The cellular telephone receives the polling message and transmits a radio frequency (RF) signal containing a reference waveform that contains certain transmission characteristics unique to the selected cellular telephone. From the received RF signal, the reference waveform is extracted and stored. Preferably, the selected cellular telephone is polled repeatedly in order to receive a sufficiently large number of reference waveforms to be able to generate an accurate fingerprint.
    Type: Grant
    Filed: June 27, 1996
    Date of Patent: March 7, 2000
    Assignee: Cellular Technical Services Company, Inc.
    Inventors: David N. Hoogerwerf, Evan R. Green, David M. Stanhope, Randy McKernan
  • Patent number: 5956635
    Abstract: A method and system for detecting a voice channel grab by a pirate in a cellular telephone network. Initially, RF signals transmitted to and from an authorized cellular telephone over the control and voice channels are monitored to track call processing activities and obtain various data that are used to detect potential voice channel grabbing attempts. The data may include such things as RSSI, change power output messages and responses, and hook-flash signal. From the data, the system looks for two events. A first event is an unexpected change or an absence of an expected change in the voice channel RF signal indicating that the pirate may be transmitting on the voice channel. The first event may be any one or more of the following: (1) a sudden upward shift in the voice channel RSSI; (2) an unexpected phase shift of either the RF signal or the SAT signal contained in the RF signal; and (3) an absence of an expected shift in the RSSI that corresponds to the change power level message from the network.
    Type: Grant
    Filed: July 16, 1996
    Date of Patent: September 21, 1999
    Assignee: Cellular Technical Services Company, Inc.
    Inventors: David N. Hoogerwerf, David M. Stanhope, Randy McKernan
  • Patent number: 5893031
    Abstract: A system and method for collecting fingerprint reference wave forms under controlled conditions includes a radio frequency (RF) enclosure designed to receive a cellular telephone. A control system, including a transmitter and receiver provides RF communications with a cellular phone placed in the enclosure. A processor controls operation of the transmitter and receiver. The processor sends commands to the cellular phone in the enclosure using the transmitter. The transmitted commands are selected to elicit a RF transmission from the cellular phone in response to the command. The receiver detects the response from the cellular telephone and generates a reference wave form indicative of the transmission characteristics of the transmitter of the cellular phone in the enclosure. The processor captures one or more reference waveforms that can be used to generate a fingerprint indicative of a transmission characteristic of the transmitter of the cellular telephone.
    Type: Grant
    Filed: June 27, 1996
    Date of Patent: April 6, 1999
    Assignee: Cellular Technical Services Company, Inc.
    Inventors: David N. Hoogerwerf, David M. Stanhope
  • Patent number: 5819171
    Abstract: A method and apparatus which provide the ability to disrupt normal completion of a specific call made through a wireless telephone system. The specified call can be forced to be immediately ended, re-routed immediately to a selectable destination, or linked to a local voice frequency interface. The disruption of the call can occur at any point in time over the duration of the call. The decision to disrupt the call, as well as which action to take against the call, can be selected manually by a human or automatically through a standard data interface provided. The call disruption apparatus can be interfaced to the wireless system through a circuit physically connected to the wireless telephone system equipment, or through a modulated radio frequency interface.
    Type: Grant
    Filed: August 31, 1995
    Date of Patent: October 6, 1998
    Assignee: Cellular Technical Services Co., Inc.
    Inventors: David N. Hoogerwerf, David M. Stanhope, William Gerrit Barrere, Evan R. Green, Randolph W. McKernan