Patents by Inventor Louis L. Scharf

Louis L. Scharf 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: 9647708
    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: Grant
    Filed: August 30, 2010
    Date of Patent: May 9, 2017
    Assignee: III HOLDINGS 1, LLC
    Inventors: Louis L. Scharf, Vijay Nagarajan, John K. Thomas
  • Patent number: 9036748
    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: November 15, 2013
    Date of Patent: May 19, 2015
    Assignee: III HOLDINGS 1, LLC
    Inventors: Vijay Nagarajan, Louis L. Scharf, Anand P. Narayan
  • Publication number: 20140314188
    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: November 15, 2013
    Publication date: October 23, 2014
    Applicant: III Holdings 1. LLC.
    Inventors: Vijay Nagarajan, Louis L. Scharf, Anand P. Narayan
  • 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: 8218697
    Abstract: An OFDMA-MIMO receiver performs a recursive interference cancellation across several correlated subbands and several receive antenna elements to demodulate complex source symbols for several users that have been coded across several subbands and transmit antennas. The iterative parallel interference canceller (PIC) is configured to work in the presence of both spatial and frequency structure introduced by the transmitter space-frequency mapping and the actual frequency selective wireless channel. The interference canceller uses mixed decisions, confidence weights, and stabilizing step sizes in a PIC receiver, which may be used with a successive decoding architecture in a receiver that employs a combination of modulation level interference cancellation with successive decoding.
    Type: Grant
    Filed: February 17, 2010
    Date of Patent: July 10, 2012
    Assignee: Rambus Inc.
    Inventors: Tommy Guess, Michael L. McCloud, Louis L. Scharf
  • 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: 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: 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: 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: 20100208854
    Abstract: An OFDMA-MIMO receiver performs a recursive interference cancellation across several correlated subbands and several receive antenna elements to demodulate complex source symbols for several users that have been coded across several subbands and transmit antennas. The iterative parallel interference canceller (PIC) is configured to work in the presence of both spatial and frequency structure introduced by the transmitter space-frequency mapping and the actual frequency selective wireless channel. The interference canceller uses mixed decisions, confidence weights, and stabilizing step sizes in a PIC receiver, which may be used with a successive decoding architecture in a receiver that employs a combination of modulation level interference cancellation with successive decoding.
    Type: Application
    Filed: February 17, 2010
    Publication date: August 19, 2010
    Inventors: Tommy Guess, Michael L. McCloud, Louis L. Scharf
  • 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