Patents by Inventor Khalid Karimullah

Khalid Karimullah 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).

  • Publication number: 20030193888
    Abstract: A method and apparatus for encoding data for transmission in a communication system provides increased efficiency in bandwidth utilization through higher data rates, lower error rates, lower power levels, and/or increased capacity. A set of orthogonal codes is partitioned into subsets. The data to be transmitted is partitioned into packets of bit sequences, each of which is mapped to an orthogonal code in an assigned subset. The number of members in a particular subset is determined by the relative transmission requirements of the data signal the subset will be used to encode.
    Type: Application
    Filed: January 3, 2002
    Publication date: October 16, 2003
    Applicant: HUGHES ELECTRONICS CORPORATION
    Inventors: Feng-Wen Sun, Khalid Karimullah, Lin-Nan Lee
  • Publication number: 20030107985
    Abstract: A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies-are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.
    Type: Application
    Filed: January 17, 2003
    Publication date: June 12, 2003
    Applicant: HUGHES ELECTRONICS CORPORATION
    Inventors: Feng-Wen Sun, Lin-Nan Lee, Khalid Karimullah
  • Publication number: 20030108089
    Abstract: A communication system is used to transmit and receive a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spreaded signal, and a control data signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol.
    Type: Application
    Filed: January 17, 2003
    Publication date: June 12, 2003
    Applicant: HUGHES ELECTRONICS CORPORATION
    Inventors: Lin-Nan Lee, Khalid Karimullah, Feng-Wen Sun, Kamran Etemad
  • Patent number: 6539050
    Abstract: A communication system is used to transmit and receive a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spreaded signal, and a control data signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol.
    Type: Grant
    Filed: June 25, 1998
    Date of Patent: March 25, 2003
    Assignee: Hughes Electronics Corporation
    Inventors: Lin-Nan Lee, Khalid Karimullah, Feng-Wen Sun, Kamran Etemad
  • Patent number: 6510147
    Abstract: A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.
    Type: Grant
    Filed: July 13, 1998
    Date of Patent: January 21, 2003
    Assignee: Hughes Electronics Corporation
    Inventors: Feng-Wen Sun, Lin-Nan Lee, Khalid Karimullah
  • Publication number: 20020181551
    Abstract: A communication system is used to transmit and receive a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spreaded signal, and a control data signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol.
    Type: Application
    Filed: July 8, 2002
    Publication date: December 5, 2002
    Applicant: HUGHES ELECTRONICS CORPORATION
    Inventors: Lin-Nan Lee, Khalid Karimullah, Feng-Wen Sun, Kamran Etemad
  • Patent number: 6396822
    Abstract: A method and apparatus for encoding data for transmission in a communication system provides increased efficiency in bandwidth utilization through higher data rates, lower error rates, lower power levels, and/or increased capacity. A set of orthogonal codes is partitioned into subsets. The data to be transmitted is partitioned into packets of bit sequences, each of which is mapped to an orthogonal code in an assigned subset. The number of members in a particular subset is determined by the relative transmission requirements of the data signal the subset will be used to encode.
    Type: Grant
    Filed: July 13, 1998
    Date of Patent: May 28, 2002
    Assignee: Hughes Electronics Corporation
    Inventors: Feng-Wen Sun, Khalid Karimullah, Lin-Nan Lee
  • Patent number: 6351240
    Abstract: An approach for electronically performing beam steering is disclosed. For electronic scanning, an n-bit quantized phase shifting approach is employed at each array element of a phased array antenna. By applying an initial phase bias, either deterministically or randomly, in each of the array elements, the performance of a phased array with n-bit quantization (even with n=2) approaches the performance of a system with no quantization. This approach can be used with linearly polarized or circularly polarized waves. For circularly polarized waves, the 2n phase shifts required of n-bit quantization are achieved in a manner that provides a simple, low-loss construction, which allows production of a low-cost reflectarray or a flat-plate lens.
    Type: Grant
    Filed: September 19, 2000
    Date of Patent: February 26, 2002
    Assignee: Hughes Electronics Corporation
    Inventors: Khalid Karimullah, Jian Song, Lin-Nan Lee, Stanley E. Kay
  • Patent number: 6178334
    Abstract: This disclosure relates to a communications network including a base station and two or more distributed cells which are remote from the base station. The cells are coupled to the base station by transmission mediums which may, for example, be cable, fiber, and/or air. Between the base station and each cell, there is a time delay or transmission time, between the time when a communication that is received at one of the two is transmitted to and is received by the other of the two. The time delays of the two cells are unique or distinct one from the other. The network includes a time responsive system which is responsive to the time delay for a communication between the base station and one of the cells. Since the time delays are distinctive, the time responsive system identifies the cell associated with the communication. The time delays of the cells may be inherent in the circuitry and transmission mediums between the base station and the cells.
    Type: Grant
    Filed: November 17, 1998
    Date of Patent: January 23, 2001
    Assignee: Hughes Electronics Corporation
    Inventors: Dong-Jye Shyy, Cathy Zatloukal, Khalid Karimullah
  • Patent number: 5423081
    Abstract: A power level control circuit for the power amplifier of a mobile cellular unit does not require a matched diode pair yet is simple in design. A sampling device, such as a directional coupler or sampling capacitor, connected to an output of the power amplifier provides a sampled RF signal output. An impedance is connected to the sampling device, and the sampling device forms a RF attenuator. A tunnel diode detector is connected to the sampling device for generating a detected d.c. output signal. Power level control (PLC) circuitry compares the detected d.c. output signal from the tunnel diode detector with a selected power level control reference signal and generates a feedback signal to the RF power amplifier to control the power level output from the amplifier. The dynamic range of this basic circuit is increased by switched attenuators, switched parallel detectors with scaled attenuation factors, or a controlled varactor diode used to change the RF coupling to the diode detector.
    Type: Grant
    Filed: August 16, 1993
    Date of Patent: June 6, 1995
    Assignee: Hughes Aircraft Company
    Inventors: Al Thiele, Sai Kwok, Khalid Karimullah
  • Patent number: 5343493
    Abstract: A personal assistance system and method for use with a cellular communication system operating over a cellular communication band and having a plurality of cell-sites. A transceiver transmits to the cell-sites a spread spectrum burst of pulses including a service request codeword indicating a request for service from a service provider. A proxy cell-phone, coupled to a preferred one of the cell-sites, originates a cellular call on the cellular communication system to a destination number of the service provider and on behalf of the transceiver to thereby create a cellular communication link between the transceiver and the service provider. A transceiver location feature provides the service provider with the geographic location of the transceiver.
    Type: Grant
    Filed: March 16, 1993
    Date of Patent: August 30, 1994
    Assignee: Hughes Aircraft Company
    Inventor: Khalid Karimullah