Patents by Inventor Mithat C. Dogan

Mithat C. Dogan 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: 7433418
    Abstract: Some embodiments store a training sequence in a communications system. The stored training sequence exhibits certain desirable characteristics when used by a peak to average power constrained modulation format. In one embodiment, a set of original ordered sequences is selected to have at least one desired property. A set of extended sequences is created from the original sequences by beginning with an element of an original sequence and cyclically appending elements of the original sequence in order to obtain a desired extended sequence length. Each extended sequence is modified using a corresponding modifying sequence, such that a training sequence can be generated from any one of the modified extended sequences. Each modifying sequence is selected so that the generated training sequence when modulated by a selected modulation format has the at least one desired property of the corresponding original ordered sequence.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: October 7, 2008
    Assignee: ArrayComm, LLC
    Inventors: Mithat C. Dogan, Mitchell D. Trott
  • Patent number: 7430606
    Abstract: The certificate revocation lists at access points of a wireless access network can be reduced. In one embodiment, an Internet Service Provider (“ISP”) connected to the wireless access network can receive a subscription request from a user terminal capable of accessing the ISP using the wireless access network. When the ISP assigns a subscription identifier to the user terminal, it also provides a service certificate signed by a certificate authority including the subscription identifier. In addition, the ISP also provides the user terminal one or more session certificates to be used to access the wireless access network, where the session certificates having a shorter validity period than the service certificate.
    Type: Grant
    Filed: October 17, 2003
    Date of Patent: September 30, 2008
    Assignee: ArrayComm, LLC
    Inventors: Branislav Meandzija, Mithat C. Dogan, Marc Goldburg
  • Patent number: 7339981
    Abstract: Embodiments of the present invention can be used to select a training sequence used by a base station and a user terminal for communications. In one embodiment, selecting the training sequence to use includes first selecting a training sequence from a set of training sequences. Then, a shift indicator is received, the shift indicator indicating a number of symbols the training sequence is to be shifted. A shifted training sequence is generated by shifting the selected training sequence by the number indicated by the received shift indicator, and the shifted training sequence is used for communication with a first transceiver on a communications channel. In another embodiment, a shift indicator indicating a number of symbols a training sequence is to be shifted is first selected, and then used to generate a shifted training sequence by shifting the training sequence by the number of symbols indicated by the selected shift indicator.
    Type: Grant
    Filed: July 9, 2002
    Date of Patent: March 4, 2008
    Assignee: ArrayComm, LLC.
    Inventor: Mithat C. Dogan
  • Patent number: 7027837
    Abstract: A system and method for communicating information between two locations via a wireless microwave link is provided. The system includes at least two antennas, each to transmit information as a narrow beam signal to be directed toward a focal point at a remote location. The antennas include at least one antenna to transmit a narrow beam signal toward a redirection point different from the focal point. A redirection device is located at the redirection point to receive the narrow beam signal from the at least one antenna element and to redirect the received narrow beam signal toward the receiver. The redirection point is located such that the narrow beam signals from the at least two antenna elements converge and overlap to form proximate to the receiver, an interference pattern that includes peaks and nulls having a peak-to-peak spacing narrower than the width of each received narrow beam signal.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: April 11, 2006
    Assignee: ArrayComm LLC.
    Inventors: Christopher R. Uhlik, Mithat C. Dogan
  • Patent number: 7016429
    Abstract: A method and apparatus are provided that generate, transmit, or receive a training sequence in a communications system, where the training sequence exhibits certain desirable characteristics when used by a peak to average power constrained modulation formal. In one embodiment, the invention includes selecting an original training sequence from a set of possible original training sequences having at least one desired property, forming a modified training sequence by modifying the original training sequence based on a corresponding modifying sequence, such that the modified training sequence exhibits the desired property of the original training sequence when used in a peak to average power constrained modulation format that would otherwise impair the desired property of the original training sequence.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: March 21, 2006
    Assignee: ArrayComm, LLC
    Inventors: Mithat C. Dogan, Mitchell D. Trott
  • Patent number: 6931030
    Abstract: A method and apparatus are provided that allows a delay to be chosen to be applied to a user terminal. According to one aspect of the present invention, the invention includes receiving a downlink broadcast burst from a base station, determining timing for an uplink burst from the received broadcast burst, selecting an amount of delay for the uplink burst, and transmitting an uplink burst to the base station using the determined timing and the selected amount of delay.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: August 16, 2005
    Assignee: ArrayComm, Inc.
    Inventor: Mithat C. Dogan
  • Publication number: 20040268126
    Abstract: Each connection can have a different symmetric key derived from a previously exchanged master secret in a symmetric key cryptography scheme. In one embodiment, the invention includes establishing a master secret between the first communications device and a second communications device, perhaps during registration. Then a connection is opened between the first communications device and the second communications device. A connection secret is generated from the master secret, and using as a symmetric key during the life of the connection.
    Type: Application
    Filed: June 24, 2003
    Publication date: December 30, 2004
    Inventors: Mithat C. Dogan, Christopher Uhlik
  • Patent number: 6801589
    Abstract: A method and apparatus are provided that allows a coarse timing approximation to be determined from analyzing only a portion of a received burst. The coarse timing can be refined by focusing on the coarse timing approximation. According to one aspect of the present invention, the invention includes receiving a burst having a known repeating core training sequence, selecting an analysis window to be substantially the same size as a multiple of a single repetition of the core training sequence, and over sampling the received burst for the portion overlapping the analysis window.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: October 5, 2004
    Assignee: ArrayComm, Inc.
    Inventor: Mithat C. Dogan
  • Patent number: 6768747
    Abstract: A method and apparatus are provided that allows timing to be determined in two steps. According to one aspect of the present invention, the invention includes searching a received digital signal burst for a known repeating core sequence, the core sequence having a first symbol sequence, and, upon finding one of the core sequences, determining sequence timing of the found core sequence using the found core sequence. The invention further includes searching the received burst for a marker sequence following the repetition of the core sequence, the marker sequence having a second symbol sequence different from the first symbol sequence and upon finding the marker sequence, determining timing of the received digital signal burst using the found marker sequence.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: July 27, 2004
    Assignee: ArrayComm, Inc.
    Inventor: Mithat C. Dogan
  • Patent number: 6731689
    Abstract: A training sequence for a radio communications system is provided. According to one aspect of the present invention, the invention includes a core sequence of symbols, a successive repetition of the core sequence, and a marker sequence having a sequence of symbols different from the core sequence.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: May 4, 2004
    Assignee: ArrayComm, Inc.
    Inventor: Mithat C. Dogan
  • Publication number: 20040008760
    Abstract: Embodiments of the present invention can be used to select a training sequence used by a base station and a user terminal for communications. In one embodiment, selecting the training sequence to use includes first selecting a training sequence from a set of training sequences. Then, a shift indicator is received, the shift indicator indicating a number of symbols the training sequence is to be shifted. A shifted training sequence is generated by shifting the selected training sequence by the number indicated by the received shift indicator, and the shifted training sequence is used for communication with a first transceiver on a communications channel. In another embodiment, a shift indicator indicating a number of symbols a training sequence is to be shifted is first selected, and then used to generate a shifted training sequence by shifting the training sequence by the number of symbols indicated by the selected shift indicator.
    Type: Application
    Filed: July 9, 2002
    Publication date: January 15, 2004
    Inventor: Mithat C. Dogan
  • Patent number: 6650881
    Abstract: A method and apparatus are provided that allows initial beamforming weights to be determined before timing or delay and frequency offset are known. According to one aspect of the present invention, the invention includes receiving a burst from a terminal at a set of spatial diversity antennas, the burst including a known training sequence and storing measurements of the received burst from each spatial diversity antenna corresponding to receive times within a selected analysis window. The invention further includes determining weights for each diversity antenna for at least a portion of the training sequence of the burst before timing for the burst has been determined, applying the determined weights to the stored measurements and determining timing for the burst based on the stored measurements to which the determined weights have been applied.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: November 18, 2003
    Assignee: ArrayComm, Inc.
    Inventor: Mithat C. Dogan
  • Patent number: 6650714
    Abstract: A method and apparatus are provided that performs spatial processing, timing estimation and frequency offset using a training sequence of a received burst. According to one aspect of the present invention, the invention includes receiving a burst having a known training sequence at a set of diversity antennas, sampling the received burst at each antenna, determining a coarse timing estimate for samples from at least one antenna, and determining a spatial weighting vector using the coarse timing estimate. The embodiment further includes applying the spatial weighting vector to the received burst samples for each antenna to form a single channel signal, determining a fine timing estimate for the single channel signal, determining a second spatial weighting vector using the fine timing estimate, applying the second spatial weighting vector to the received burst samples for each antenna to form a second single channel signal, and demodulating the second single channel signal.
    Type: Grant
    Filed: April 24, 2001
    Date of Patent: November 18, 2003
    Assignee: ArrayComm, Inc.
    Inventors: Mithat C. Dogan, Paul Petrus, Mitchell D. Trott
  • Publication number: 20030156594
    Abstract: In one embodiment, the present invention includes a slot in a repeating time division frame with a first training sequence, an information sequence after the first training sequence, and a second training sequence after the information sequence. In some embodiments either the first or the second training sequences indicates a type for the information sequence, such as a random access channel message and a traffic channel message, a configuration message, a channel assignment message, or a data traffic message.
    Type: Application
    Filed: September 30, 2002
    Publication date: August 21, 2003
    Inventors: Mitchell D. Trott, Mithat C. Dogan, Paul Petrus, Sundar G. Sankaran
  • Publication number: 20020150182
    Abstract: A method and apparatus are provided that performs spatial processing, timing estimation and frequency offset using a training sequence of a received burst. According to one aspect of the present invention, the invention includes receiving a burst having a known training sequence at a set of diversity antennas, sampling the received burst at each antenna, determining a coarse timing estimate for samples from at least one antenna, and determining a spatial weighting vector using the coarse timing estimate. The embodiment further includes applying the spatial weighting vector to the received burst samples for each antenna to form a single channel signal, determining a fine timing estimate for the single channel signal, determining a second spatial weighting vector using the fine timing estimate, applying the second spatial weighting vector to the received burst samples for each antenna to form a second single channel signal, and demodulating the second single channel signal.
    Type: Application
    Filed: April 24, 2001
    Publication date: October 17, 2002
    Inventors: Mithat C. Dogan, Paul Petrus, Mitchell D. Trott
  • Publication number: 20020122498
    Abstract: A training sequence for a radio communications system is provided. According to one aspect of the present invention, the invention includes a core sequence of symbols, a successive repetition of the core sequence, and a marker sequence having a sequence of symbols different from the core sequence.
    Type: Application
    Filed: February 19, 2002
    Publication date: September 5, 2002
    Inventor: Mithat C. Dogan
  • Patent number: 5459668
    Abstract: The invention includes an arrangement of actual sensors in an antenna array with a computation of higher-order statistics to provide virtual second order statistics corresponding to virtual elements in the array; employment of the actual and virtual elements of the array for covariance based direction finding; and, with the addition of a separate sensor spaced from the main array, suppression of non-Gaussian measurement noise. This is accomplished employing cross-correlation of the virtual sensors or alternately calibrating the existing actual array employing cross-correlation of the array and it's virtual sensors.
    Type: Grant
    Filed: June 4, 1993
    Date of Patent: October 17, 1995
    Assignee: University Of Southern California
    Inventors: Mithat C. Dogan, Jerry M. Mendel