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).
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Patent number: 9736832Abstract: 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: GrantFiled: March 10, 2016Date of Patent: August 15, 2017Assignee: Intel CorporationInventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Patent number: 9628120Abstract: 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: GrantFiled: December 7, 2015Date of Patent: April 18, 2017Assignee: Scintera Networks LLCInventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
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Patent number: 9461697Abstract: 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: GrantFiled: February 27, 2014Date of Patent: October 4, 2016Assignee: Scintera Networks LLCInventors: Qian Yu, Yan Wang, Olivier Charlon, Rajeev Krishnamoorthy
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Publication number: 20160262134Abstract: 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: ApplicationFiled: March 10, 2016Publication date: September 8, 2016Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Publication number: 20160087657Abstract: 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: ApplicationFiled: December 7, 2015Publication date: March 24, 2016Inventors: Qian YU, Yan WANG, Rajeev KRISHNAMOORTHY
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Patent number: 9288800Abstract: 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: GrantFiled: April 8, 2013Date of Patent: March 15, 2016Assignee: Intel CorporationInventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Patent number: 9209841Abstract: 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 valuesType: GrantFiled: January 28, 2014Date of Patent: December 8, 2015Assignee: SCINTERA NETWORKS LLCInventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
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Publication number: 20150244414Abstract: 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: ApplicationFiled: February 27, 2014Publication date: August 27, 2015Inventors: Qian Yu, Yan Wang, Olivier Charlon, Rajeev Krishnamoorthy
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Publication number: 20150214987Abstract: 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 valuesType: ApplicationFiled: January 28, 2014Publication date: July 30, 2015Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
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Patent number: 8937993Abstract: 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: GrantFiled: May 17, 2013Date of Patent: January 20, 2015Assignee: Scintera Networks LLCInventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
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Publication number: 20140341316Abstract: 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: ApplicationFiled: May 17, 2013Publication date: November 20, 2014Inventors: Qian Yu, Yan Wang, Rajeev Krishnamoorthy
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Patent number: 8805304Abstract: 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: GrantFiled: January 4, 2012Date of Patent: August 12, 2014Assignee: Scintera Networks LLCInventors: Qian Yu, Rajeev Krishnamoorthy, Olivier Charlon
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Publication number: 20130286962Abstract: 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: ApplicationFiled: April 8, 2013Publication date: October 31, 2013Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Publication number: 20130099862Abstract: 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: ApplicationFiled: January 4, 2012Publication date: April 25, 2013Applicant: SCINTERA NETWORKS, INC.Inventors: Qian YU, Rajeev KRISHNAMOORTHY, Olivier CHARLON
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Patent number: 8428037Abstract: 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: GrantFiled: October 22, 2009Date of Patent: April 23, 2013Assignee: Intel CorporationInventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Patent number: 8345637Abstract: 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: GrantFiled: July 2, 2009Date of Patent: January 1, 2013Assignee: Intel CorporationInventors: Robert W. Heath, Rajeev Krishnamoorthy, Arogyaswami J. Paulraj, Peroor K. Sebastian
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Publication number: 20100142636Abstract: 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: ApplicationFiled: October 22, 2009Publication date: June 10, 2010Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Publication number: 20100046429Abstract: 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: ApplicationFiled: July 2, 2009Publication date: February 25, 2010Inventors: Robert W. Heath, JR., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Patent number: 7586873Abstract: 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: GrantFiled: April 7, 2005Date of Patent: September 8, 2009Assignee: Intel CorporationInventors: Robert W. Heath, Jr., Rajeev Krishnamoorthy, Peroor K. Sebastian, Arogyaswami J. Paulraj
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Publication number: 20080248802Abstract: 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: ApplicationFiled: April 9, 2007Publication date: October 9, 2008Inventor: Rajeev Krishnamoorthy