Patents by Inventor Allen LeRoy Limberg

Allen LeRoy Limberg 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).

  • Publication number: 20190334755
    Abstract: Transmitting apparatus and receiving apparatus for communication systems using coded orthogonal frequency-division multiplexed (COFDM) dual-subcarrier modulation (DCM) signals. The same coded data is mapped both to COFDM subcarriers located in the lower-frequency half spectrum of the DCM signal and to COFDM subcarriers located in its upper-frequency half spectrum. The mapping of COFDM subcarriers in those half spectra employ labeling diversity. A primary design goal in some preferred labeling diversity formats is to support reception of DCM with less error when accompanied by interfering additive white Gaussian noise (AWGN). A primary design goal in some preferred labeling diversity formats is to reduce the peak-to-average power ratio (PAPR) of the COFDM DCM signals. In preferred forms of COFDM DCM signal, the quadrature amplitude modulation (QAM) of COFDM subcarriers is Gray mapped to position palindromic lattice-point labels along one of the diagonals of each square QAM constellation.
    Type: Application
    Filed: June 27, 2019
    Publication date: October 31, 2019
    Inventor: Allen LeRoy Limberg
  • Publication number: 20190199572
    Abstract: Transmitting apparatus and receiving apparatus for communication systems using coded orthogonal frequency-division multiplexed (COFDM) dual-subcarrier modulation (DCM) signals. The same coded data is mapped both to COFDM subcarriers located in the lower-frequency half spectrum of the DCM signal and to COFDM subcarriers located in its upper-frequency half spectrum. The mapping of COFDM subcarriers in those half spectra employ labeling diversity preferred for reception of DCM with less error when accompanied by interfering additive white Gaussian noise (AWGN). In preferred forms of COFDM DCM signal, the quadrature amplitude modulation (QAM) of COFDM subcarriers is Gray mapped to position palindromic lattice-point labels along one of the diagonals of each square QAM constellation.
    Type: Application
    Filed: February 14, 2019
    Publication date: June 27, 2019
    Inventor: Allen LeRoy Limberg
  • Publication number: 20190132171
    Abstract: Transmitting apparatus and receiving apparatus for communication systems using coded orthogonal frequency-division multiplexed (COFDM) dual-subcarrier modulation (DCM) signals. The same coded data is mapped both to COFDM subcarriers located in the lower-frequency half spectrum of the DCM signal and to COFDM subcarriers located in its upper-frequency half spectrum. The mapping of COFDM subcarriers in those half spectra employ labeling diversity preferred for reception of DCM with less error when accompanied by interfering additive white Gaussian noise (AWGN). In preferred forms of COFDM DCM signal, the quadrature amplitude modulation (QAM) of COFDM subcarriers is Gray mapped to position palindromic lattice-point labels along one of the diagonals of each square QAM constellation.
    Type: Application
    Filed: July 18, 2018
    Publication date: May 2, 2019
    Inventor: Allen LeRoy Limberg
  • Publication number: 20190007255
    Abstract: Receivers for coded orthogonal frequency-division multiplexed (COFDM) signals conveying the same coded data both in lower-frequency and upper-frequency sidebands thereof. Apparatus for performing a complex synchrodyne of COFDM signal to baseband is followed by apparatus for extracting the COFDM subcarriers of the lower-frequency and upper-frequency sidebands of the COFDM signal from the in-phase and quadrature-phase results of the complex synchrodyne. The COFDM subcarriers of the lower-frequency sideband as converted to baseband are supplied to apparatus for demodulating and demapping those subcarriers to recover a first set of coded data. The COFDM subcarriers of the upper-frequency sideband as converted to baseband are supplied to apparatus for demodulating and demapping those subcarriers to recover a second set of coded data. A diversity combiner combines the first and second sets of coded data for subsequent decoding.
    Type: Application
    Filed: July 17, 2018
    Publication date: January 3, 2019
    Inventor: Allen LeRoy Limberg
  • Patent number: 10171280
    Abstract: Prior-art receivers for double-sideband coded orthogonal frequency-division modulation (COFDM) signal, such as receivers for digital television (DTV) broadcasting, have folded the frequency spectrum in half by synchrodyne to baseband before discrete Fourier transform (DFT) and de-mapping quadrature amplitude-modulation (QAM) of COFDM signal subcarriers, thus to improve signal-to-noise ratio by 6 dB. Single-sideband or independent-sideband COFDM receivers that perform DFT and demapping of QAM of COFDM signal subcarriers in an unfolded frequency spectrum can improve signal-to-noise ratio by 8.5 dB by maximal-ratio combining bits of demapping results. Such improvement is achieved even when such a receiver is arranged for receiving a DSB-COFDM signal, in which double-sideband signal the frequency spectra of the lower and upper sidebands mirror each other. Reception range is increased by about a third over that of receivers which fold the frequency in half during synchrodyne to baseband.
    Type: Grant
    Filed: July 3, 2017
    Date of Patent: January 1, 2019
    Inventor: Allen LeRoy Limberg
  • Publication number: 20180123857
    Abstract: In independent-sideband (ISB) coded orthogonal frequency-division multiplexing (COFDM) modulation, data is transmitted twice in each COFDM symbol interval. The data is mapped both to OFDM carriers located in the lower sideband of the ISB COFDM modulation signal and to OFDM carriers located in its upper sideband. Preferably, the ordering of OFDM carriers modulated by given coded data is the same in both the lower and upper sidebands of the COFDM modulation signal. Preferably, bits of the labels in the map of QAM symbol constellations in the each sideband more likely to experience error correspond to bits of the labels in the map of QAM symbol constellations in the other sideband less likely to experience error.
    Type: Application
    Filed: October 29, 2017
    Publication date: May 3, 2018
    Inventor: Allen LeRoy Limberg
  • Publication number: 20180034677
    Abstract: Prior-art receivers for double-sideband coded orthogonal frequency-division modulation (COFDM) signal, such as receivers for digital television (DTV) broadcasting, have folded the frequency spectrum in half by synchrodyne to baseband before discrete Fourier transform (DFT) and de-mapping quadrature amplitude-modulation (QAM) of COFDM signal subcarriers, thus to improve signal-to-noise ratio by 6 dB. Single-sideband or independent-sideband COFDM receivers that perform DFT and demapping of QAM of COFDM signal subcarriers in an unfolded frequency spectrum can improve signal-to-noise ratio by 8.5 dB by maximal-ratio combining bits of demapping results. Such improvement is achieved even when such a receiver is arranged for receiving a DSB-COFDM signal, in which double-sideband signal the frequency spectra of the lower and upper sidebands mirror each other. Reception range is increased by about a third over that of receivers which fold the frequency in half during synchrodyne to baseband.
    Type: Application
    Filed: July 3, 2017
    Publication date: February 1, 2018
    Inventor: Allen LeRoy Limberg
  • Patent number: 9762360
    Abstract: In transmitter apparatus for a digital television broadcasting system, internet-protocol (IP) packets of digital television information are subjected to multilevel coding (MLC) before being Gray-mapped to quadrature-amplitude-modulation (QAM) constellations. The constituent codes of the MLC comprise respective low-density parity-check (LDPC) inner coding. Preferably, the LDPC inner coding is LDPC convolutional coding. The QAM constellations are used in coded orthogonal frequency-division modulation (COFDM) of plural carrier waves up-converted to a radio-frequency broadcast television channel. In receiver apparatus for the digital television broadcasting system the results of de-mapping QAM constellations recovered from demodulating the COFDM carrier waves are de-interleaved, and the LDPC constituent codes of the MLC are independently decoded in parallel with decoding results time-interleaved to recover the IP packets of digital television information.
    Type: Grant
    Filed: September 28, 2015
    Date of Patent: September 12, 2017
    Inventor: Allen LeRoy Limberg
  • Patent number: 9647865
    Abstract: Transmitter apparatus to broadcast coded orthogonal frequency-division multiplexed (COFDM) radio-frequency carriers conveying low-density parity-check (LPDC) coding transmits the same coded DTV signals twice some time apart. The coded DTV signals of initial transmissions and of final transmissions are mapped to quadrature amplitude modulation (QAM) of the COFDM carriers according to first and second patterns, respectively. Bits that map to lattice points in the first mapping pattern more likely to experience error are mapped to lattice points in the second mapping pattern less likely to experience error. Bits that map to lattice points in the second mapping pattern more likely to experience error are mapped to lattice points in the first mapping pattern less likely to experience error. Receiver apparatus demaps QAM symbols in the earlier and later transmissions of twice-transmitted COFDM signals and maximal-ratio combines the de-mapping results at bit level, rather than symbol level.
    Type: Grant
    Filed: July 19, 2016
    Date of Patent: May 9, 2017
    Inventor: Allen LeRoy Limberg
  • Patent number: 9497056
    Abstract: Transmitter apparatus transmits metadata together with data, at least part of which metadata specifies the version of coded orthogonal frequency-division modulation (COFDM) broadcasting standard it uses for transmitting. Some of the metadata is conveyed by prescribed signature modulation of pilot carrier waves dispersed in one or another of prescribed patterns among the COFDM carrier waves that convey interleaved forward-error-correction coded digital signals. Receiver apparatus detects that metadata by searching for a prescribed signature modulation of the continual pilot carrier waves in those transmissions. Preferably, Barker modulation of the continual pilot carriers near the conclusion of each COFDM frame signals the start of the next COFDM frame to the receiver apparatus.
    Type: Grant
    Filed: June 8, 2015
    Date of Patent: November 15, 2016
    Inventors: Allen LeRoy Limberg, Arthur Webb Allison, III
  • Publication number: 20160087649
    Abstract: In transmitter apparatus for a digital television broadcasting system, internet-protocol (IP) packets of digital television information are subjected to multilevel coding (MLC) before being Gray-mapped to quadrature-amplitude-modulation (QAM) constellations. The constituent codes of the MLC comprise respective low-density parity-check (LDPC) inner coding. Preferably, the LDPC inner coding is LDPC convolutional coding. The QAM constellations are used in coded orthogonal frequency-division modulation (COFDM) of plural carrier waves up-converted to a radio-frequency broadcast television channel. In receiver apparatus for the digital television broadcasting system the results of de-mapping QAM constellations recovered from demodulating the COFDM carrier waves are de-interleaved, and the LDPC constituent codes of the MLC are independently decoded in parallel with decoding results time-interleaved to recover the IP packets of digital television information.
    Type: Application
    Filed: September 28, 2015
    Publication date: March 24, 2016
    Inventor: Allen LeRoy Limberg
  • Patent number: 9253428
    Abstract: Digital television (DTV) broadcasting using COFDM modulation is designed to modulate orthogonal frequency-division-multiplexed (OFDM) mid-band carriers with metadata including synchronization signals and transmission-mode signals. DTV signals modulate OFDM carriers occupying portions of the frequency spectrum of the transmission channel that extend in frequency both below and above these mid-band carriers. The OFDM midband carriers are capable of signaling when a new broadcast service is used that differs from the one disclosed. The signaling is provided by modulating the midband carriers with respective elements of signature sequences, each of which signature sequences is composed of Zadoff-Chu sequences and repetitive pseudo-random sequences scrambled by a Zadoff-Chu sequence.
    Type: Grant
    Filed: May 20, 2015
    Date of Patent: February 2, 2016
    Inventors: Arthur Webb Allison, III, Allen LeRoy Limberg
  • Publication number: 20150358648
    Abstract: In transmitter apparatus for a digital television (DTV) broadcasting system, internet-protocol (IP) packets of digital television information are subjected to multilevel concatenated Bose-Chaudhuri-Hocquenghem (BCH) coding and low-density parity-check convolutional coding (LDPCCC) before being bit-interleaved and mapped to quadrature-amplitude-modulation (QAM) constellations. The QAM constellations are used in coded orthogonal frequency-division modulation (COFDM) of plural carrier waves up-converted to a radio-frequency broadcast television channel. In receiver apparatus for the DTV broadcasting system the results of de-mapping QAM constellations recovered from demodulating the COFDM carrier waves are de-interleaved, and the constituent LDPCCC codewords are decoded to recover constituent BCH codewords of the multilevel BCH coding. The constituent BCH codewords are decoded to correct remnant bit errors in them.
    Type: Application
    Filed: June 9, 2014
    Publication date: December 10, 2015
    Inventor: Allen LeRoy Limberg
  • Publication number: 20150358106
    Abstract: Transmitter apparatus transmits metadata together with data, at least part of which metadata specifies the version of coded orthogonal frequency-division modulation (COFDM) broadcasting standard it uses for transmitting. Some of the metadata is conveyed by prescribed signature modulation of pilot carrier waves dispersed in one or another of prescribed patterns among the COFDM carrier waves that convey interleaved forward-error-correction coded digital signals. Receiver apparatus detects that metadata by searching for a prescribed signature modulation of the continual pilot carrier waves in those transmissions. Preferably, Barker modulation of the continual pilot carriers near the conclusion of each COFDM frame signals the start of the next COFDM frame to the receiver apparatus.
    Type: Application
    Filed: June 8, 2015
    Publication date: December 10, 2015
    Inventors: Allen LeRoy Limberg, Arthur Webb Allison, III
  • Publication number: 20150341586
    Abstract: Digital television (DTV) broadcasting using COFDM modulation is designed to modulate orthogonal frequency-division-multiplexed (OFDM) mid-band carriers with metadata including synchronization signals and transmission-mode signals. DTV signals modulate OFDM carriers occupying portions of the frequency spectrum of the transmission channel that extend in frequency both below and above these mid-band carriers. The OFDM midband carriers are capable of signaling when a new broadcast service is used that differs from the one disclosed. The signaling is provided by modulating the midband carriers with respective elements of signature sequences, each of which signature sequences is composed of Zadoff-Chu sequences and repetitive pseudo-random sequences scrambled by a Zadoff-Chu sequence.
    Type: Application
    Filed: May 20, 2015
    Publication date: November 26, 2015
    Inventors: Arthur Webb Allison, III, Allen LeRoy Limberg
  • Patent number: 9143375
    Abstract: Transmitter apparatus to broadcast coded orthogonal frequency-division multiplexed (COFDM) radio-frequency carriers conveying low-density parity-check (LPDC) coding transmits the same coded DTV signals twice some time apart. The coded DTV signals of initial transmissions and of final transmissions are mapped to quadrature amplitude modulation (QAM) of the COFDM carriers according to first and second patterns, respectively. Bits that map to lattice points in the first mapping pattern more likely to experience error are mapped to lattice points in the second mapping pattern less likely to experience error. Bits that map to lattice points in the second mapping pattern more likely to experience error are mapped to lattice points in the first mapping pattern less likely to experience error. Receiver apparatus combines the earlier and later transmissions of twice-transmitted COFDM signals as part of iterative procedures for de-mapping QAM and decoding the LDPC coding of the DTV signals.
    Type: Grant
    Filed: March 8, 2015
    Date of Patent: September 22, 2015
    Inventor: Allen LeRoy Limberg
  • Patent number: 9143785
    Abstract: Turbo-coded data are transmitted using quadrature amplitude modulation (QAM) of COFDM carrier waves in digital television (DTV) broadcast systems. The QAM symbol constellations map the parity bits of the turbo coded data so as to be de-mapped with higher confidence levels than the data bits, facilitating turbo decoding. A preferred DTV receiver delays the first transmissions of time-slices of a service selected for iterative-diversity reception to concur with second transmissions of those time-slices. The complex coordinates of QAM constellations in the delayed first transmission and the second transmission of the same time-slice are combined by a maximal-ratio QAM combiner after COFDM demodulation, but before de-mapping QAM constellations and turbo decoding. In a less-preferred DTV receiver, QAM constellations in the delayed first transmission of each time-slice and in the second transmission of the same time-slice are de-mapped separately.
    Type: Grant
    Filed: October 25, 2012
    Date of Patent: September 22, 2015
    Inventor: Allen LeRoy Limberg
  • Publication number: 20150256376
    Abstract: Transmitter apparatus to broadcast coded orthogonal frequency-division multiplexed (COFDM) radio-frequency carriers conveying low-density parity-check (LPDC) coding transmits the same coded DTV signals twice some time apart. The coded DTV signals of initial transmissions and of final transmissions are mapped to quadrature amplitude modulation (QAM) of the COFDM carriers according to first and second patterns, respectively. Bits that map to lattice points in the first mapping pattern more likely to experience error are mapped to lattice points in the second mapping pattern less likely to experience error. Bits that map to lattice points in the second mapping pattern more likely to experience error are mapped to lattice points in the first mapping pattern less likely to experience error. Receiver apparatus combines the earlier and later transmissions of twice-transmitted COFDM signals as part of iterative procedures for de-mapping QAM and decoding the LDPC coding of the DTV signals.
    Type: Application
    Filed: March 8, 2015
    Publication date: September 10, 2015
    Inventor: Allen LeRoy Limberg
  • Patent number: 9124396
    Abstract: Receivers with capability for iterative-diversity reception of COFDM digital television transmissions of repeated similarly coded data are described. Also described are receivers with capabilities for receiving COFDM digital television transmissions in which earlier transmissions of coded data are later followed by subsequent transmissions of the same data differently coded. The receivers use maximal-ratio code combining techniques for repeated components in the COFDM digital television transmissions. The receivers use turbo decoding techniques for concatenated coding of data in the COFDM digital television transmissions.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: September 1, 2015
    Inventor: Allen LeRoy Limberg
  • Patent number: 9118352
    Abstract: In a DTV transmitter the bits of shortened BCH codewords that exhibit undesirably low densities of ONEs are ONEs' complemented before being further coded, and used to modulate carrier waves. In a DTV receiver the further coding is decoded after demodulation. The results of such decoding are processed to recover successive shortened BCH codewords, some of which are in TRUE form and others of which have had their bits ONEs' complemented. Each shortened BCH codeword is extended to full length with ZEROs, and decoding is attempted. Successful decoding confirms that the shortened BCH codeword was received in TRUE form. If decoding is unsuccessful, the bits of the shortened BCH codeword as received are ONEs' complemented, extended to full length with ZEROs, and decoding is attempted. Successful decoding confirms that the shortened BCH codeword was received in ONEs' complemented form and has subsequently been converted to TRUE form.
    Type: Grant
    Filed: December 26, 2012
    Date of Patent: August 25, 2015
    Inventor: Allen LeRoy Limberg