Patents by Inventor Rajeev Krishnamoorthy

Rajeev Krishnamoorthy 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: 9736832
    Abstract: A wireless communications system is presented that adapts its mode of operation between spatial and non-spatial multiplexing in response to transmission-specific variables. Mode determination logic determines, in response to a received signal, if spatial or non-spatial multiplexing should be used to transmit a subscriber datastream between the BTS and the UE. The mode determination logic receives a measure of a transmission characteristic of the signal, compares the transmission characteristic to a transmission characteristic threshold and selects either spatial or non-spatial multiplexing in response to the comparison. The transmission characteristic includes at least one of delay spread, post-processing signal-to-noise ratio, CRC failure, residual inter-symbol interference, mean square error, coherence time, and path loss.
    Type: Grant
    Filed: March 10, 2016
    Date of Patent: August 15, 2017
    Assignee: Intel Corporation
    Inventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Patent number: 9628120
    Abstract: A system includes a crest-factor reduction circuit, a signal analyzer, and a pre-distortion circuit. The crest-factor reduction circuit reduces a crest factor of a baseband signal and generates a feedforward signal. The signal analyzer generates parameters based on the feedforward signal and an output signal from a power amplifier. The pre-distortion circuit generates a pre-distorted baseband signal based on the parameters for input to the power amplifier.
    Type: Grant
    Filed: December 7, 2015
    Date of Patent: April 18, 2017
    Assignee: Scintera Networks LLC
    Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
  • Patent number: 9461697
    Abstract: A transceiver coupled to an antenna includes: (a) a multi-port filter having a bidirectional port coupled to the antenna, at least one input port and at least one output port; (b) a transmit datapath receiving a transmission signal and providing the transmission signal for transmission by the antenna through the multi-port filter, the transmit datapath being coupled to the input port of the multi-port filter; (c) a receive datapath receiving a reception signal from the antenna, the receive datapath being coupled to the output port of the multi-port filter; (d) a band-pass filter coupled to the antenna for receiving a sampled signal that includes intermodulation components between two or more of an external signal, the transmission signal and the reception signal; and (e) a monitoring and cancellation circuit receiving the transmission signal, the reception signal and the sampled signal to cancel the intermodulation components.
    Type: Grant
    Filed: February 27, 2014
    Date of Patent: October 4, 2016
    Assignee: Scintera Networks LLC
    Inventors: Qian Yu, Yan Wang, Olivier Charlon, Rajeev Krishnamoorthy
  • Publication number: 20160262134
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing in an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal.
    Type: Application
    Filed: March 10, 2016
    Publication date: September 8, 2016
    Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Publication number: 20160087657
    Abstract: A system includes a crest-factor reduction circuit, a signal analyzer, and a pre-distortion circuit. The crest-factor reduction circuit reduces a crest factor of a baseband signal and generates a feedforward signal. The signal analyzer generates parameters based on the feedforward signal and an output signal from a power amplifier. The pre-distortion circuit generates a pre-distorted baseband signal based on the parameters for input to the power amplifier.
    Type: Application
    Filed: December 7, 2015
    Publication date: March 24, 2016
    Inventors: Qian YU, Yan WANG, Rajeev KRISHNAMOORTHY
  • Patent number: 9288800
    Abstract: Embodiments of a base transceiver station and method for transmitting are described herein. In some embodiments, data is transmitted over a downlink channel in accordance with a selected one of a plurality of transmission modes. The base transceiver station may be configurable to transmit data in accordance with each of the transmission modes. One of the transmissions modes may be selected for the data transmission based at least in part on feedback reported by a subscriber unit. The transmission modes include at least a single antenna mode, a transmit diversity mode, and a spatial multiplexing mode.
    Type: Grant
    Filed: April 8, 2013
    Date of Patent: March 15, 2016
    Assignee: Intel Corporation
    Inventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Patent number: 9209841
    Abstract: A pre-distortion circuit for a power amplifier may include: (a) a digital interface for receiving a complex-value digital baseband signal; (b) a mixed-signal pre-distortion circuit adaptively controlled by a set of parameter values, receiving the complex-value digital baseband signal to provide a pre-distorted signal for input to the power amplifier, the mixed-signal pre-distortion circuit may include: (i) digital pre-distortion circuit that transforms the complex-value digital baseband signal to a pre-distorted complex-value digital baseband signal by applying to the complex-value digital baseband signal a memory-less non-linear gain and a polynomial function based on the complex-value digital baseband signal one or more delayed copies of the complex-value digital baseband signal; and (ii) up-converter that converts the pre-distorted complex-value digital baseband signal to the pre-distorted signal; and (c) a signal analyzer receiving an output signal from the power amplifier to provide the parameter values
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: December 8, 2015
    Assignee: SCINTERA NETWORKS LLC
    Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
  • Publication number: 20150244414
    Abstract: A transceiver coupled to an antenna includes: (a) a multi-port filter having a bidirectional port coupled to the antenna, at least one input port and at least one output port; (b) a transmit datapath receiving a transmission signal and providing the transmission signal for transmission by the antenna through the multi-port filter, the transmit datapath being coupled to the input port of the multi-port filter; (c) a receive datapath receiving a reception signal from the antenna, the receive datapath being coupled to the output port of the multi-port filter; (d) a band-pass filter coupled to the antenna for receiving a sampled signal that includes intermodulation components between two or more of an external signal, the transmission signal and the reception signal; and (e) a monitoring and cancellation circuit receiving the transmission signal, the reception signal and the sampled signal to cancel the intermodulation components.
    Type: Application
    Filed: February 27, 2014
    Publication date: August 27, 2015
    Inventors: Qian Yu, Yan Wang, Olivier Charlon, Rajeev Krishnamoorthy
  • Publication number: 20150214987
    Abstract: A pre-distortion circuit for a power amplifier may include: (a) a digital interface for receiving a complex-value digital baseband signal; (b) a mixed-signal pre-distortion circuit adaptively controlled by a set of parameter values, receiving the complex-value digital baseband signal to provide a pre-distorted signal for input to the power amplifier, the mixed-signal pre-distortion circuit may include: (i) digital pre-distortion circuit that transforms the complex-value digital baseband signal to a pre-distorted complex-value digital baseband signal by applying to the complex-value digital baseband signal a memory-less non-linear gain and a polynomial function based on the complex-value digital baseband signal one or more delayed copies of the complex-value digital baseband signal; and (ii) up-converter that converts the pre-distorted complex-value digital baseband signal to the pre-distorted signal; and (c) a signal analyzer receiving an output signal from the power amplifier to provide the parameter values
    Type: Application
    Filed: January 28, 2014
    Publication date: July 30, 2015
    Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
  • Patent number: 8937993
    Abstract: A crest factor reduction (CFR) circuit reduces the peak-to-average (PAR) power of a digitally modulated signal in a complex baseband is achieved by post-processing the input signal, with negligible increase in out-of-band emissions. The CFR circuit takes advantage of a procedure that solves for an optimum CFR using a constraint-optimization approach. In one embodiment, the CFR circuit, which receives an input signal and provides an output signal, includes: (a) an error generation circuit that receives the input signal and provides an error signal representative of a measure of circuit-induced distortion and a delayed input signal, the delayed input signal being the input signal delayed by a predetermined value; (b) a linear-phase filter receiving the error signal to provide a correction signal; and (c) a summer that subtracts the correction from the delayed input signal to provide the output signal.
    Type: Grant
    Filed: May 17, 2013
    Date of Patent: January 20, 2015
    Assignee: Scintera Networks LLC
    Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
  • Publication number: 20140341316
    Abstract: A crest factor reduction (CFR) circuit reduces the peak-to-average (PAR) power of a digitally modulated signal in a complex baseband is achieved by post-processing the input signal, with negligible increase in out-of-band emissions. The CFR circuit takes advantage of a procedure that solves for an optimum CFR using a constraint-optimization approach. In one embodiment, the CFR circuit, which receives an input signal and provides an output signal, includes: (a) an error generation circuit that receives the input signal and provides an error signal representative of a measure of circuit-induced distortion and a delayed input signal, the delayed input signal being the input signal delayed by a predetermined value; (b) a linear-phase filter receiving the error signal to provide a correction signal; and (c) a summer that subtracts the correction from the delayed input signal to provide the output signal.
    Type: Application
    Filed: May 17, 2013
    Publication date: November 20, 2014
    Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
  • Patent number: 8805304
    Abstract: An RF linearizer and an associated method are provided for linearizing a power amplifier. The RF linearizer may include: (a) a quadrature up-converter for up-converting a baseband input signal that is to be transmitted by the power amplifier; (b) an RF analog predistorter controlled by a set of coefficients for predistorting the up-converted input signal; (c) a down-converter for down-converting an output signal of the power amplifier; (d) an error monitor receiving the down-converted output signal and the input signal for providing an error signal; and (e) a signal analyzer receiving the error signal, the signal analyzer using an out-of-band power spectrum of the error signal to optimize the set of coefficients. The input signal may have an in-phase component and a quadrature component.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: August 12, 2014
    Assignee: Scintera Networks LLC
    Inventors: Qian Yu, Rajeev Krishnamoorthy, Olivier Charlon
  • Publication number: 20130286962
    Abstract: Embodiments of a base transceiver station and method for transmitting are described herein. In some embodiments, data is transmitted over a downlink channel in accordance with a selected one of a plurality of transmission modes. The base transceiver station may be configurable to transmit data in accordance with each of the transmission modes. One of the transmissions modes may be selected for the data transmission based at least in part on feedback reported by a subscriber unit. The transmission modes include at least a single antenna mode, a transmit diversity mode, and a spatial multiplexing mode.
    Type: Application
    Filed: April 8, 2013
    Publication date: October 31, 2013
    Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Publication number: 20130099862
    Abstract: An RF linearizer and an associated method are provided for linearizing a power amplifier. The RF linearizer may include: (a) a quadrature up-converter for up-converting a baseband input signal that is to be transmitted by the power amplifier; (b) an RF analog predistorter controlled by a set of coefficients for predistorting the up-converted input signal; (c) a down-converter for down-converting an output signal of the power amplifier; (d) an error monitor receiving the down-converted output signal and the input signal for providing an error signal; and (e) a signal analyzer receiving the error signal, the signal analyzer using an out-of-band power spectrum of the error signal to optimize the set of coefficients. The input signal may have an in-phase component and a quadrature component.
    Type: Application
    Filed: January 4, 2012
    Publication date: April 25, 2013
    Applicant: SCINTERA NETWORKS, INC.
    Inventors: Qian YU, Rajeev KRISHNAMOORTHY, Olivier CHARLON
  • Patent number: 8428037
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing. In an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal.
    Type: Grant
    Filed: October 22, 2009
    Date of Patent: April 23, 2013
    Assignee: Intel Corporation
    Inventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Patent number: 8345637
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber data stream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing.
    Type: Grant
    Filed: July 2, 2009
    Date of Patent: January 1, 2013
    Assignee: Intel Corporation
    Inventors: Robert W. Heath, Rajeev Krishnamoorthy, Arogyaswami J. Paulraj, Peroor K. Sebastian
  • Publication number: 20100142636
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing. In an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal.
    Type: Application
    Filed: October 22, 2009
    Publication date: June 10, 2010
    Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Publication number: 20100046429
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing. In an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal.
    Type: Application
    Filed: July 2, 2009
    Publication date: February 25, 2010
    Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Patent number: 7586873
    Abstract: A wireless communications adapts its mode of operation between spatial multiplexing and non-spatial multiplexing in response to transmission-specific variables. An embodiment of a wireless communications system for transmitting information between a base transceiver station and a subscriber unit includes mode determination logic. The mode determination logic is in communication with the base transceiver station and the subscriber unit. The mode determination logic determines, in response to a received signal, if a subscriber datastream should be transmitted between the base transceiver station and the subscriber unit utilizing spatial multiplexing or non-spatial multiplexing. In an embodiment, the mode determination logic has an input for receiving a measure of a transmission characteristic related to the received signal.
    Type: Grant
    Filed: April 7, 2005
    Date of Patent: September 8, 2009
    Assignee: Intel Corporation
    Inventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
  • Publication number: 20080248802
    Abstract: A method of a multiple antenna node within a wireless network selecting an antenna pattern is disclosed. The method includes identifying a plurality of transmission paths through the node. One of a plurality of antenna patterns formed by the multiple antenna node is selected, providing a desired level of link quality through each of the identified plurality of transmission paths. The node wirelessly communicates through the identified transmission paths.
    Type: Application
    Filed: April 9, 2007
    Publication date: October 9, 2008
    Inventor: Rajeev Krishnamoorthy