Patents by Inventor Raja V. Tamma
Raja V. Tamma 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: 9853787Abstract: Methods and system for carrier frequency offset (CFO) estimation are described. The method includes determining correlation values between a plurality of samples from a received signal and a plurality of reference signals corresponding to a plurality of CFO candidates. A set of correlation values which exceeds a threshold is determined and a corresponding CFO candidate for each correlation value in the set is selected. A CFO estimate based on an interpolation of selected CFO candidates is then calculated.Type: GrantFiled: August 25, 2015Date of Patent: December 26, 2017Assignee: NXP USA, INC.Inventors: Mihai-Ionut Stanciu, Raja V. Tamma, Khurram Waheed
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Patent number: 9794056Abstract: A method and apparatus for identifying a search window of carrier-frequency-offset-corrected samples in which a first intermediate signal from a demodulator does not exceed a predetermined threshold, convolving a second intermediate signal from the demodulator within the search window with a predefined pattern to provide a convolution result, determining if an absolute peak of the convolution result exceeds a preamble pattern confirmation threshold, in response to the absolute peak of the convolution result exceeding the preamble confirmation threshold, confirming a preamble pattern detection event to provide a confirmed preamble pattern detection event of a confirmed preamble pattern, and receiving a signal including the confirmed preamble pattern to provide a received digital signal extracted from the signal.Type: GrantFiled: October 3, 2016Date of Patent: October 17, 2017Assignee: NXP USA, Inc.Inventors: Raja V. Tamma, Claudio Rey
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Patent number: 9729195Abstract: At least one embodiment of a correlator comprising a plurality of correlator taps is configurable to provide synchronization and symbol modulation for a plurality of modulation systems. Among other uses, at least one embodiment of the correlator can provide a coarse symbol timing value. In response to determining the coarse symbol timing value, a receiver can receive a signal. Among other uses, at least one embodiment of the correlator can provide a carrier frequency offset (CFO) estimate. In response to determining the CFO estimate, a receiver can receive a signal.Type: GrantFiled: December 7, 2015Date of Patent: August 8, 2017Assignee: NXP USA, Inc.Inventors: Raja V. Tamma, Justin A. Fritz, Mihai-Ionut M. Stanciu
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Publication number: 20170099077Abstract: At least one embodiment of a correlator comprising a plurality of correlator taps is configurable to provide synchronization and symbol modulation for a plurality of modulation systems. Among other uses, at least one embodiment of the correlator can provide a coarse symbol timing value. In response to determining the coarse symbol timing value, a receiver can receive a signal. Among other uses, at least one embodiment of the correlator can provide a carrier frequency offset (CFO) estimate. In response to determining the CFO estimate, a receiver can receive a signal.Type: ApplicationFiled: December 7, 2015Publication date: April 6, 2017Inventors: Raja V. Tamma, Justin A. Fritz, Mihai-Ionut M. Stanciu
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Publication number: 20160381581Abstract: Methods and system for carrier frequency offset (CFO) estimation are described. The method includes determining correlation values between a plurality of samples from a received signal and a plurality of reference signals corresponding to a plurality of CFO candidates. A set of correlation values which exceeds a threshold is determined and a corresponding CFO candidate for each correlation value in the set is selected. A CFO estimate based on an interpolation of selected CFO candidates is then calculated.Type: ApplicationFiled: August 25, 2015Publication date: December 29, 2016Inventors: MIHAI-IONUT STANCIU, RAJA V. TAMMA, KHURRAM WAHEED
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Patent number: 9385909Abstract: A technique for detecting symbols includes performing an over-sized discrete Fourier transform (DFT) operation on a received signal that includes at least two repeated symbols. A sum of signal characteristics for subcarriers of one or more possible symbols are determined based on the DFT operation. A sum of signal characteristics for non-subcarriers of the one or more possible symbols is determined based on the DFT operation. Finally, a determination is made as to whether one or more of the one or more possible symbols is detected based on the sum of signal characteristics for the subcarriers and sum of signal characteristics for the non-subcarriers.Type: GrantFiled: October 8, 2013Date of Patent: July 5, 2016Assignee: Freescale Semiconductor, Inc.Inventors: Raja V. Tamma, Kevin Traylor
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Patent number: 9282525Abstract: Methods and systems are disclosed for frequency-domain symbol and frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency components associated with subcarriers within the multi-carrier communication signals. Symbol synchronization is performed in the frequency domain by performing correlation(s) between frequency components of the received signal and frequency-domain synchronization symbol(s). After symbol synchronization, frame synchronization correlation is also performed in the frequency domain between frequency components of the received signal and frequency-domain synchronization symbol(s). The disclosed embodiments are particularly useful for symbol and frame synchronization in multi-carrier received signals for power line communication (PLC) systems and/or other harsh noisy communication environments.Type: GrantFiled: June 24, 2013Date of Patent: March 8, 2016Assignee: Freescale Semiconductor, Inc.Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor, Khurram Waheed
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Patent number: 9112754Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.Type: GrantFiled: October 8, 2013Date of Patent: August 18, 2015Assignee: Freescale Semiconductor, Inc.Inventor: Raja V. Tamma
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Patent number: 9106499Abstract: Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.Type: GrantFiled: June 24, 2013Date of Patent: August 11, 2015Assignee: Freescale Semiconductor, Inc.Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor
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Patent number: 9100261Abstract: Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved.Type: GrantFiled: June 24, 2013Date of Patent: August 4, 2015Assignee: Freescale Semiconductor, Inc.Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor
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Patent number: 9008223Abstract: A transmitter and method for processing a digitally modulated communication signal, which may reduce peak-to-average-power-ratio (PAPR) while maintaining acceptable error rates is disclosed. After subcarrier mapping, a first digital representation of the signal is upsampled into a second digital representation, which is transformed into a first time domain representation. Samples whose magnitudes exceed a magnitude limit are limited to that limit to produce a second time domain representation. The second time domain representation is transformed to a third frequency domain representation, which is downsampled into a fourth frequency domain representation. In addition to the in-band subcarriers, some out-of-band subcarriers adjacent to the frequency band are preserved while the remaining out-of-band subcarriers are eliminated to produce a fifth frequency domain representation.Type: GrantFiled: December 24, 2013Date of Patent: April 14, 2015Assignee: Freescale Semiconductor, Inc.Inventors: Raja V. Tamma, Kevin B. Traylor, Jianqiang Zeng
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Publication number: 20150098514Abstract: A technique for generating a bit log-likelihood ratio (LLR) in a communication system includes generating a demodulated signal based on a received symbol and a reference symbol. An input for a bit LLR generator is generated based on the demodulated signal and a normalization value that is based on the received symbol or the reference symbol. A bit LLR is generated for the received symbol, using the bit LLR generator, based on the input.Type: ApplicationFiled: October 8, 2013Publication date: April 9, 2015Inventor: Raja V. Tamma
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Publication number: 20150098530Abstract: A technique for detecting symbols includes performing an over-sized discrete Fourier transform (DFT) operation on a received signal that includes at least two repeated symbols. A sum of signal characteristics for subcarriers of one or more possible symbols are determined based on the DFT operation. A sum of signal characteristics for non-subcarriers of the one or more possible symbols is determined based on the DFT operation. Finally, a determination is made as to whether one or more of the one or more possible symbols is detected based on the sum of signal characteristics for the subcarriers and sum of signal characteristics for the non-subcarriers.Type: ApplicationFiled: October 8, 2013Publication date: April 9, 2015Inventors: Raja V. Tamma, Kevin Traylor
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Publication number: 20140376674Abstract: Methods and systems are disclosed for frequency-domain frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency domain components associated with subcarriers within the multi-carrier communication signals. A sliding-window correlation (e.g., two-dimensional sliding window) is applied to the received symbols represented in the frequency domain to detect frame boundaries for multi-carrier signals. The sliding-window frame synchronization can be applied by itself or can be applied in combination with one or more additional frame synchronization stages. The disclosed embodiments are particularly useful for frame synchronization of multi-carrier signals in PLC (power line communication) systems.Type: ApplicationFiled: June 24, 2013Publication date: December 25, 2014Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor
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Publication number: 20140376540Abstract: Methods and systems are disclosed for frequency-domain symbol and frame synchronization for multi-carrier communication systems. Received signals are sampled and converted into frequency components associated with subcarriers within the multi-carrier communication signals. Symbol synchronization is performed in the frequency domain by performing correlation(s) between frequency components of the received signal and frequency-domain synchronization symbol(s). After symbol synchronization, frame synchronization correlation is also performed in the frequency domain between frequency components of the received signal and frequency-domain synchronization symbol(s). The disclosed embodiments are particularly useful for symbol and frame synchronization in multi-carrier received signals for power line communication (PLC) systems and/or other harsh noisy communication environments.Type: ApplicationFiled: June 24, 2013Publication date: December 25, 2014Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor, Khurram Waheed
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Publication number: 20140376648Abstract: Methods and systems are disclosed for frequency-domain amplitude normalization for symbol correlation in multi-carrier communication systems. Digital samples associated with input signals received from a communication medium are processed using a Fast Fourier Transform (FFT) to generate complex frequency components. Each complex frequency component is normalized with respect to its amplitude, and the frequency-domain, amplitude-normalized frequency components are multiplied with frequency components for reference symbol(s) to generate frequency-domain correlation values. These frequency-domain correlation values are analyzed to determine if a correlation exists between the amplitude-normalized frequency components and the predetermined reference frequency components. A correlation detection output is then generated that indicates whether or not a symbol synchronization was achieved.Type: ApplicationFiled: June 24, 2013Publication date: December 25, 2014Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor
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Publication number: 20140376667Abstract: Methods and systems are disclosed for frequency-domain carrier blanking in multi-carrier communication systems. When excessive energy is detected in one or more subcarriers within a received symbol for multi-carrier communications, those subcarriers are blanked for subsequent demodulation in order to avoid corruption of the demodulated data. A conversion from time-domain digital samples to frequency-domain values using an FFT (Fast Fourier Transform) and a threshold detector are utilized to detect corrupted subcarriers. Further, this frequency-domain carrier blanking can be implemented dynamically on a symbol-by-symbol basis to further improve demodulation performance by reducing decoding errors. The disclosed embodiments are particularly useful for improving demodulation performance in power line communication (PLC) systems.Type: ApplicationFiled: June 24, 2013Publication date: December 25, 2014Inventors: Jianqiang Zeng, Steven M. Bosze, Raja V. Tamma, Kevin B. Traylor
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Patent number: 7933372Abstract: A method for processing a plurality of symbol streams is provided. The method includes receiving a first symbol stream, wherein the first symbol stream has a corresponding first number of retransmissions. The method further includes receiving a second symbol stream, wherein the second symbol stream has a corresponding second number of retransmissions. The method further includes selecting the first symbol stream for decoding, if the first number of retransmissions is greater than the second number of retransmissions.Type: GrantFiled: March 8, 2007Date of Patent: April 26, 2011Assignee: Freescale Semiconductor, Inc.Inventors: Oghenekome F. Oteri, Leo G. Dehner, Jayesh H. Kotecha, Raja V. Tamma
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Publication number: 20080219388Abstract: A method for processing a plurality of symbol streams is provided. The method includes receiving a first symbol stream, wherein the first symbol stream has a corresponding first number of retransmissions. The method further includes receiving a second symbol stream, wherein the second symbol stream has a corresponding second number of retransmissions. The method further includes selecting the first symbol stream for decoding, if the first number of retransmissions is greater than the second number of retransmissions.Type: ApplicationFiled: March 8, 2007Publication date: September 11, 2008Inventors: Oghenekome F. Oteri, Leo G. Dehner, Jayesh H. Kotecha, Raja V. Tamma