Patents by Inventor Amitava Ghosh

Amitava Ghosh 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: 5764188
    Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.
    Type: Grant
    Filed: April 24, 1997
    Date of Patent: June 9, 1998
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, John Dougles Reed, Walter Joseph Rozanski, Jr., Kevin Andrew Buford
  • Patent number: 5736964
    Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.
    Type: Grant
    Filed: February 16, 1996
    Date of Patent: April 7, 1998
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, John Douglas Reed, Walter Joseph Rozanski, Jr., Kevin Andrew Buford
  • Patent number: 5727028
    Abstract: The apparatus includes a demodulator (70) responsive to a first received symbol (68) associated with a first transmitted symbol (39). The demodulator has a plurality of outputs (72) and produces a first set of outputs (99). The demodulator (70) is also responsive to a second received symbol (68) associated with a second transmitted symbol (39), and produces a second set of outputs (99). A coherent detector (100) receives some outputs from the first set of outputs (99), producing an estimate of the first transmitted symbol. The coherent detector also receives some outputs from the second set of outputs (99), producing an estimate of the second transmitted symbol. A first energy value (135) and an index (101) are associated with the first estimate, while a second energy value (135) is associated with the second estimate.
    Type: Grant
    Filed: July 31, 1996
    Date of Patent: March 10, 1998
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, Kamyar Rohani
  • Patent number: 5629934
    Abstract: A transmitter transmits the desired signal using a continuous duty cycle at transmission rates of less than full rate (FIG. 6 ). The energy used in each power control group is related to the transmission rate. By repeating the power control groups, time division diversity (FIG. 6 ) is provided. In the receiver, the received power control groups are analyzed and compared to several levels of energy thresholds (73, 75, 77, 79). The results of the comparisons are converted into a power control signal (74, 76, 78, 80, 81) and returned to the mobile. The mobiles are capable of selecting the appropriate bit (93) and adjusting their power (94). Alternatively, an indicator of the transmission rate can be forwarded (155) in advance of the frame. The receiver compares a power estimate with the threshold for the transmission rate indicated (166).
    Type: Grant
    Filed: June 30, 1995
    Date of Patent: May 13, 1997
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, Kamyar Rohani
  • Patent number: 5583886
    Abstract: Each of a plurality of transmitters (31-37) transmits (62) one of a plurality of known signals. The known signals being known to a receiver (40). The receiver (40) then measures the known signals (63); and using those measurements, estimates the plurality of channel responses (64). The channel responses are then used to determine a power ratio parameter (65) and a phase correction parameter (66).
    Type: Grant
    Filed: December 3, 1992
    Date of Patent: December 10, 1996
    Assignee: Motorola, Inc.
    Inventors: Kamyar Rohani, Amitava Ghosh, R. Mark Harrison
  • Patent number: 5508708
    Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.
    Type: Grant
    Filed: May 8, 1995
    Date of Patent: April 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Amitava Ghosh, John D. Reed, Walter J. Rozanski, Jr., Kevin A. Buford
  • Patent number: 5406585
    Abstract: A method is provided of discerning a signal of a desired user on a channel having a desired user and a plurality of interfering users, each, upon occasion, transmitting an identifiable, known pilot symbol. The method includes the steps of determining a channel response of the desired user and each of the interfering users and calculating a metric equal to the squared difference between a received signal and a sum of the products of transmitted signals and channel responses for the desired user and each of the plurality of interfering users. The method also includes the step of discerning the signal of the desired user based, at least in part, upon a minimum metric.
    Type: Grant
    Filed: November 30, 1992
    Date of Patent: April 11, 1995
    Assignee: Motorola, Inc.
    Inventors: Kamyar Rohani, Amitava Ghosh