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: 7876810
    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 post-processed SINR. The estimated pre-processed SINR is obtained from averages of estimated symbol energies and estimated noise variances, or from related statistical procedures.
    Type: Grant
    Filed: November 4, 2005
    Date of Patent: January 25, 2011
    Assignee: Rambus Inc.
    Inventors: Michael L McCloud, Vijay Nagarajan
  • Publication number: 20100329402
    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: August 30, 2010
    Publication date: December 30, 2010
    Applicant: RAMBUS INC.
    Inventors: Louis L. Scharf, Vijay Nagarajan, John K. Thomas
  • Patent number: 7826516
    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: July 24, 2006
    Date of Patent: November 2, 2010
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 7808937
    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: November 10, 2005
    Date of Patent: October 5, 2010
    Assignee: Rambus, Inc.
    Inventors: Michael L McCloud, Vijay Nagarajan
  • Publication number: 20100238981
    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: March 19, 2010
    Publication date: September 23, 2010
    Inventors: Vijay Nagarajan, Louis Scharf, Anami P. Narayan
  • Publication number: 20100220824
    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: March 25, 2010
    Publication date: September 2, 2010
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, GaganDeep Singh Lamba
  • Patent number: 7787572
    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 subchannel 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: Grant
    Filed: August 15, 2005
    Date of Patent: August 31, 2010
    Assignee: Rambus Inc.
    Inventors: Louis L. Scharf, Vijay Nagarajan
  • Publication number: 20100208774
    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 sub channel symbol level).
    Type: Application
    Filed: April 28, 2010
    Publication date: August 19, 2010
    Applicant: RAMBUS INC.
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Publication number: 20100177856
    Abstract: A receiver is configured for canceling intra-cell and inter-cell interference in coded, multiple-access, spread-spectrum transmissions that propagate through frequencyselective 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: Application
    Filed: March 25, 2010
    Publication date: July 15, 2010
    Inventors: Tommy Guess, Michael L. McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 7715508
    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: May 11, 2010
    Assignee: Tensorcomm, Incorporated
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 7711075
    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: May 4, 2010
    Assignee: Tensorcomm Incorporated
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 7702048
    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: April 20, 2010
    Assignee: Tensorcomm, Incorporated
    Inventors: Tommy Guess, Michael L McCloud, Vijay Nagarajan, Gagandeep Singh Lamba
  • Patent number: 7697595
    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: May 11, 2006
    Date of Patent: April 13, 2010
    Assignee: Tensorcomm Incorporated
    Inventors: Vijay Nagarajan, Louis L Scharf, Anand P Narayan
  • Patent number: 7463609
    Abstract: The receiver includes a Rake receiver for separating a received signal into multipath components, an interference selector for selecting interference symbols corresponding to interfering paths and subchannels, a synthesizer for synthesizing an interference signal from selected paths and estimated subchannel symbols, and a canceller for constructing a projection operator or a scale-invariant subtraction operator to cancel selected interference in multipath components of the received signal, or from the received signal itself. The interference canceller may use a sequence of symbol estimates to simultaneously cancel inter-channel interference and inter-symbol interference. Interference cancellers may be placed at one or more locations within the receiver chain.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: December 9, 2008
    Assignee: Tensorcomm, Inc
    Inventors: Louis L. Scharf, Vijay Nagarajan
  • Publication number: 20070263704
    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: May 11, 2006
    Publication date: November 15, 2007
    Inventors: Vijay Nagarajan, Louis Scharf, Anand Narayan
  • Publication number: 20070242460
    Abstract: One version of a light beacon has a base, a light source, and a controller. The base is suitable for installing the light beacon within a building at a location so as emit light over a coverage area of the building. The light source is movably supported by the base. The controller controls the light source so that the light provided by the light source moves over the coverage area and so that the light provided by the light sources flashes. The light beacon may also have a lock that that determines an extent of movement of the light source.
    Type: Application
    Filed: April 18, 2006
    Publication date: October 18, 2007
    Inventor: Vijay Nagarajan
  • Publication number: 20070110136
    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: July 24, 2006
    Publication date: May 17, 2007
    Inventors: Tommy Guess, Michael McCloud, Vijay Nagarajan, Gagandeep Lamba
  • Publication number: 20070110134
    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: Application
    Filed: June 13, 2006
    Publication date: May 17, 2007
    Inventors: Tommy Guess, Michael McCloud, Vijay Nagarajan, Gagandeep Lamba
  • Publication number: 20070110133
    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: Application
    Filed: June 13, 2006
    Publication date: May 17, 2007
    Inventors: Tommy Guess, Michael McCloud, Vijay Nagarajan, Gagandeep Lamba
  • Publication number: 20070110132
    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: Application
    Filed: June 13, 2006
    Publication date: May 17, 2007
    Inventors: Tommy Guess, Michael McCloud, Vijay Nagarajan, Gagandeep Lamba