Patents by Inventor Mohammad A. Khajehnejad

Mohammad A. Khajehnejad 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: 9083404
    Abstract: Methods and systems for transmission are shown that include iteratively generating an optimized precoder matrix and optimized linear filters for multiple receivers, where the optimized precoder matrix is based on a linear filter from a previous iteration and the optimized linear filters the multiple receivers are based on a precoder matrix from a previous iteration, precoding an input stream using the iteratively generated optimized precoder matrix to produce transmission streams for the multiple receivers, where at least one receiver has a plurality of associated transmission streams, and transmitting the transmission streams with multiple antennas to the receivers.
    Type: Grant
    Filed: September 16, 2011
    Date of Patent: July 14, 2015
    Assignee: NEC Laboratories America, Inc.
    Inventors: Mohammad A. Khojastepour, Mohammad A. Khajehnejad, Guosen Yue
  • Patent number: 8648742
    Abstract: Systems and methods in accordance with embodiments of the invention utilize a CS architecture based on a sub-linear time recovery process (with reduced memory requirements). In several embodiments, a novel structured measurement matrix is exploited during signal acquisition allowing the use of a recovery process based on relatively simple computational primitives making it more amenable to implementation in a fully-integrated form. One embodiment of the invention includes an analog front end configured to receive an analog input signal, and CS sampling circuitry connected to an output of the analog front end and configured to generate a plurality of measurements using a structured measurement matrix, where each row of the structured measurement matrix is generated using a different predetermined check node. In addition, the CS sampling circuitry is configured to generate the plurality of measurements at a rate that is less than the Nyquist rate of the analog input signal.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: February 11, 2014
    Assignee: California Institute of Technology
    Inventors: Mohammad A. Khajehnejad, Babak Hassibi, Juhwan Yoo
  • Patent number: 8520764
    Abstract: Beamforming systems and methods are disclosed. In accordance with one method, indications of channel matrices for a plurality of receivers are obtained. Further, a beamformer matrix is formulated as a linear combination of columns of hermitians of the channel matrices. In addition, coefficients of the hermitians in the linear combination are determined to compute the beamformer matrix such that a lowest reception rate among reception rates of each of the receivers is maximized. Data signals are transmitted to the receivers by applying the computed beamformer matrix to data symbols to maximize the lowest reception rate.
    Type: Grant
    Filed: July 29, 2011
    Date of Patent: August 27, 2013
    Assignee: NEC Laboratories America, Inc.
    Inventors: Mohammad A. Khojastepour, Mohammad A. Khajehnejad, Karthik Sundaresan, Sampath Rangarajan
  • Publication number: 20120249353
    Abstract: Systems and methods in accordance with embodiments of the invention utilize a CS architecture based on a sub-linear time recovery process (with reduced memory requirements). In several embodiments, a novel structured measurement matrix is exploited during signal acquisition allowing the use of a recovery process based on relatively simple computational primitives making it more amenable to implementation in a fully-integrated form. One embodiment of the invention includes an analog front end configured to receive an analog input signal, and CS sampling circuitry connected to an output of the analog front end and configured to generate a plurality of measurements using a structured measurement matrix, where each row of the structured measurement matrix is generated using a different predetermined check node. In addition, the CS sampling circuitry is configured to generate the plurality of measurements at a rate that is less than the Nyquist rate of the analog input signal.
    Type: Application
    Filed: February 27, 2012
    Publication date: October 4, 2012
    Applicant: California Institute of Technology
    Inventors: Mohammad A. Khajehnejad, Babak Hassibi, Juhwan Yoo
  • Publication number: 20120069924
    Abstract: Methods and systems for transmission are shown that include iteratively generating an optimized precoder matrix and optimized linear filters for multiple receivers, where the optimized precoder matrix is based on a linear filter from a previous iteration and the optimized linear filters the multiple receivers are based on a precoder matrix from a previous iteration, precoding an input stream using the iteratively generated optimized precoder matrix to produce transmission streams for the multiple receivers, where at least one receiver has a plurality of associated transmission streams, and transmitting the transmission streams with multiple antennas to the receivers.
    Type: Application
    Filed: September 16, 2011
    Publication date: March 22, 2012
    Applicant: NEC LABORATORIES AMERICA, INC.
    Inventors: Mohammad A. Khojastepour, Mohammad A. Khajehnejad, Guosen Yue
  • Publication number: 20120027117
    Abstract: Beamforming systems and methods are disclosed. In accordance with one method, indications of channel matrices for a plurality of receivers are obtained. Further, a beamformer matrix is formulated as a linear combination of columns of hermitians of the channel matrices. In addition, coefficients of the hermitians in the linear combination are determined to compute the beamformer matrix such that a lowest reception rate among reception rates of each of the receivers is maximized. Data signals are transmitted to the receivers by applying the computed beamformer matrix to data symbols to maximize the lowest reception rate.
    Type: Application
    Filed: July 29, 2011
    Publication date: February 2, 2012
    Applicant: NEC Laboratories America, Inc.
    Inventors: Mohammad A. Khojastepour, Mohammad A. Khajehnejad, Karthik Sundaresan, Sampath Rangarajan