Patents by Inventor Vijay Nagarajan

Vijay Nagarajan 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: 8654689
    Abstract: An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: February 18, 2014
    Assignee: Rambus Inc.
    Inventors: Michael L. McCloud, Vijay Nagarajan
  • Publication number: 20130343498
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Application
    Filed: June 7, 2013
    Publication date: December 26, 2013
    Applicant: Rambus Inc.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20130336363
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Application
    Filed: June 3, 2013
    Publication date: December 19, 2013
    Applicant: Rambus Inc.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 8588349
    Abstract: A receiver employs low-rate processing to synthesize the effect of high-rate interference in a received multi-rate signal. Each high-rate subchannel is analyzed on its low-rate descendents to produce symbol estimates for each low-rate symbol interval. The symbol estimates are applied to low-rate descendent subchannels, which are then combined to synthesize the effects of the high-rate interference. An interference canceller processes the synthesized interference with the received signal for producing an interference-cancelled signal. Alternatively, analogous steps may be applied at high-rate to analyze, synthesize, and cancel the effects of low-rate interference in a multi-rate signal.
    Type: Grant
    Filed: October 5, 2011
    Date of Patent: November 19, 2013
    Assignee: Rambus Inc.
    Inventors: Vijay Nagarajan, Louis L. Scharf, Anand P. Narayan
  • Patent number: 8462901
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: June 11, 2013
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 8457262
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: June 4, 2013
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 8446975
    Abstract: This invention teaches to the details of an interference suppressing receiver for suppressing intra-cell and inter-cell interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency selective communication channels to a multiplicity of receive antennas. The receiver is designed or adapted through the repeated use of symbol-estimate weighting, subtractive suppression with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be designed, adapted, and implemented explicitly in software or programmed hardware, or implicitly in standard RAKE-based hardware either within the RAKE (i.e., at the finger level) or outside the RAKE (i.e., at the user or subchannel symbol level). Embodiments may be employed in user equipment on the forward link or in a base station on the reverse link. It may be adapted to general signal processing applications where a signal is to be extracted from interference.
    Type: Grant
    Filed: February 13, 2012
    Date of Patent: May 21, 2013
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 8300745
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Grant
    Filed: March 25, 2010
    Date of Patent: October 30, 2012
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20120147817
    Abstract: This invention teaches to the details of an interference suppressing receiver for suppressing intra-cell and inter-cell interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency selective communication channels to a multiplicity of receive antennas. The receiver is designed or adapted through the repeated use of symbol-estimate weighting, subtractive suppression with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be designed, adapted, and implemented explicitly in software or programmed hardware, or implicitly in standard RAKE-based hardware either within the RAKE (i.e., at the finger level) or outside the RAKE (i.e., at the user or subchannel symbol level). Embodiments may be employed in user equipment on the forward link or in a base station on the reverse link. It may be adapted to general signal processing applications where a signal is to be extracted from interference.
    Type: Application
    Filed: February 13, 2012
    Publication date: June 14, 2012
    Applicant: RAMBUS INC
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 8121176
    Abstract: This invention teaches to the details of an interference canceling receiver for canceling intra-cell and inter-cell interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency selective communication channels to a multiplicity of receive antennas. The receiver is designed or adapted through the repeated use of symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be designed, adapted, and implemented explicitly in software or programmed hardware, or implicitly in standard RAKE-based hardware either within the RAKE (i.e., at the finger level) or outside the RAKE (i.e., at the user or subchannel symbol level). Embodiments may be employed in user equipment on the forward link or in a base station on the reverse link. It may be adapted to general signal processing applications where a signal is to be extracted from interference.
    Type: Grant
    Filed: October 29, 2010
    Date of Patent: February 21, 2012
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20120027138
    Abstract: A receiver employs low-rate processing to synthesize the effect of high-rate interference in a received multi-rate signal. Each high-rate subchannel is analyzed on its low-rate descendents to produce symbol estimates for each low-rate symbol interval. The symbol estimates are applied to low-rate descendent subchannels, which are then combined to synthesize the effects of the high-rate interference. An interference canceller processes the synthesized interference with the received signal for producing an interference-cancelled signal. Alternatively, analogous steps may be applied at high-rate to analyze, synthesize, and cancel the effects of low-rate interference in a multi-rate signal.
    Type: Application
    Filed: October 5, 2011
    Publication date: February 2, 2012
    Applicant: RAMBUS INC.
    Inventors: Vijay Nagarajan, Louis L. Scharf, Anand P. Narayan
  • Patent number: 8064498
    Abstract: A receiver employs low-rate processing to synthesize the effect of high-rate interference in a received multi-rate signal. Each high-rate subchannel is analyzed on its low-rate descendents to produce symbol estimates for each low-rate symbol interval. The symbol estimates are applied to low-rate descendent subchannels, which are then combined to synthesize the effects of the high-rate interference. An interference canceller processes the synthesized interference with the received signal for producing an interference-cancelled signal. Alternatively, analogous steps may be applied at high-rate to analyze, synthesize, and cancel the effects of low-rate interference in a multi-rate signal.
    Type: Grant
    Filed: March 19, 2010
    Date of Patent: November 22, 2011
    Assignee: Rambus Inc.
    Inventors: Vijay Nagarajan, Louis L. Scharf, Armand P. Narayan
  • Publication number: 20110255573
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Application
    Filed: June 28, 2011
    Publication date: October 20, 2011
    Applicant: RAMBUS INC.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20110200151
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimate. Receiver embodiments may be implemented explicitly in software of programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user of subchannel symbol level).
    Type: Application
    Filed: April 27, 2011
    Publication date: August 18, 2011
    Applicant: RAMBUS INC.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagan Deep Singh Lamba
  • Patent number: 7991088
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequency-selective communication channels. The receiver employs iterative symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be implemented explicitly in software or programmed hardware, or implicitly in standard Rake-based hardware either within the Rake (i.e., at the finger level) or outside the Rake (i.e., at the user or subchannel symbol level).
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: August 2, 2011
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20110116049
    Abstract: Systems and methods for displaying three-dimensional (3D) images are described. In particular, the systems can include a display block made from a transparent material with optical elements three-dimensionally disposed therein. Each optical element becomes luminous when illuminated by a light ray. The systems can also include a computing device configured to generate two-dimensional (2D) images formatted to create 3D images when projected on the display block, by a video projector coupled to the computing device. The video projector is configured to project the 2D images on the block to create the 3D images by causing a set of the passive optical elements to become luminous. Various other systems and methods are described for displaying 3D images.
    Type: Application
    Filed: January 24, 2011
    Publication date: May 19, 2011
    Applicant: The Trustees of Columbia University in the City of New York
    Inventors: Shree K. Nayar, Vijay A. Nagarajan
  • Publication number: 20110080923
    Abstract: Interference is cancelled from a baseband signal by synthesizing interference from estimated symbols in interfering subchannels. The estimated symbols are hard-coded, soft weighted, or zeroed, depending on the value of an estimated pre-processed signal-to-interference-and-noise ratio (SINR) in each subchannel in order to maximize a postprocessed SINR. The estimated pre-processed SINR is obtained from averages of estimated symbol energies and estimated noise variances, or from related statistical procedures.
    Type: Application
    Filed: December 13, 2010
    Publication date: April 7, 2011
    Applicant: RAMBUS INC.
    Inventors: Michael L. McCloud, Vijay Nagarajan
  • Publication number: 20110069796
    Abstract: A multi-mode receiver includes a channel decomposition module (e.g., a Rake receiver) for separating a received signal into multipath components, an interference selector for selecting interfering paths and subchannels, a synthesizer for synthesizing interference signals from selected sub channel symbol estimates, and an interference canceller for cancelling selected interference in the received signal. At least one of the channel decomposition module, the synthesizer, and the interference canceller are configurable for processing multi-mode signals.
    Type: Application
    Filed: December 1, 2010
    Publication date: March 24, 2011
    Applicant: RAMBUS INC.
    Inventors: Louis L. Scharf, Vijay Nagarajan
  • Publication number: 20110044378
    Abstract: This invention teaches to the details of an interference canceling receiver for canceling intra-cell and inter-cell interference in coded, multiple-access, spread spectrum transmissions that propagate through frequency selective communication channels to a multiplicity of receive antennas. The receiver is designed or adapted through the repeated use of symbol-estimate weighting, subtractive cancellation with a stabilizing step-size, and mixed-decision symbol estimates. Receiver embodiments may be designed, adapted, and implemented explicitly in software or programmed hardware, or implicitly in standard RAKE-based hardware either within the RAKE (i.e., at the finger level) or outside the RAKE (i.e., at the user or subchannel symbol level). Embodiments may be employed in user equipment on the forward link or in a base station on the reverse link. It may be adapted to general signal processing applications where a signal is to be extracted from interference.
    Type: Application
    Filed: October 29, 2010
    Publication date: February 24, 2011
    Applicant: RAMBUS INC.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20110019656
    Abstract: An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.
    Type: Application
    Filed: September 28, 2010
    Publication date: January 27, 2011
    Applicant: RAMBUS INC.
    Inventors: Michael L. McCloud, Vijay Nagarajan