Patents by Inventor Ernest C. Chen
Ernest C. Chen 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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Publication number: 20090016431Abstract: Methods and apparatuses for maximizing power and spectral efficiencies in a wireless communication system are disclosed. The invention is particularly useful for layered modulation applications because power levels for such applications are relatively high. A layered modulation signal comprises an upper and a lower layer signal that interfere with each other within the same frequency band such that the upper layer signal can be demodulated directly from the layered modulation signal, and the lower layer signal can be demodulated after subtracting the first layer signal from the layered modulation signal. The invention applies one or more of the following four signal schemes in a communication signal including varying the symbol rate (rather than the code rate), reducing or eliminating the guard band, reducing excess signal bandwidth and employing layered modulation within the guard band of the legacy signal.Type: ApplicationFiled: September 9, 2008Publication date: January 15, 2009Applicant: The DIRECTV Group, Inc.Inventor: Ernest C. Chen
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Patent number: 7474710Abstract: An apparatus and method for receiving layered modulation signals is disclosed. A typical method includes receiving a layered modulation signal including an upper layer signal and a lower layer signal, demodulating and decoding the upper layer signal from the received layered modulation signal, estimating an upper layer amplitude factor and an upper layer phase factor from the received layered modulation signal. A substantially ideal upper layer signal is reconstructed from the demodulated and decoded upper layer signal including matching an ideal amplitude and an ideal phase by applying the upper layer amplitude factor and the upper layer phase factor to the reconstructed ideal upper layer signal. Finally, the reconstructed ideal upper layer signal is subtracted from the received layered modulation signal to produce the lower layer signal for processing.Type: GrantFiled: October 3, 2003Date of Patent: January 6, 2009Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Jeng-Hong Chen, Kenneth Shum, Joungheon Oh
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Patent number: 7471735Abstract: Methods and apparatuses for maximizing power and spectral efficiencies in a wireless communication system are disclosed. The invention is particularly useful for layered modulation applications because power levels for such applications are relatively high. A layered modulation signal comprises an upper and a lower layer signal that interfere with each other within the same frequency band such that the upper layer signal can be demodulated directly from the layered modulation signal, and the lower layer signal can be demodulated after subtracting the first layer signal from the layered modulation signal. The invention applies one or more of the following four signal schemes in a communication signal including varying the symbol rate (rather than the code rate), reducing or eliminating the guard band, reducing excess signal bandwidth and employing layered modulation within the guard band of the legacy signal.Type: GrantFiled: October 16, 2003Date of Patent: December 30, 2008Assignee: The DIRECTV Group, Inc.Inventor: Ernest C. Chen
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Patent number: 7469019Abstract: A method and apparatus for optimizing a system for transmitting a layered modulated signal is disclosed. The method comprises the steps of defining the system in terms of a set of system parameters, including an optimal power separation S between a power of a first modulation layer and a power of a second modulation layer and a required system carrier-to-noise ratio (CNRS), determining an optimal power separation S to minimize the error rate of a lower layer modulated signal BERL, and selecting the remaining system parameters in the set of system parameters using the determined optimal power separation S.Type: GrantFiled: January 18, 2007Date of Patent: December 23, 2008Assignee: The DIRECTV Group, Inc.Inventors: Weizheng Wang, Guangcai Zhou, Tung-Sheng Lin, Ernest C. Chen, Joseph Santoru, William C. Lindsey
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Patent number: 7466282Abstract: A method and apparatus for receiving signals transmitted from a plurality of communications satellites. An apparatus in accordance with the present invention comprises a reflecting surface having a focal point, and a plurality of low noise block down converters with feedhorns (LNBFs), each LNBF having a boresight, wherein at least a first LNBF receives signals in a first frequency band transmitted from a first communication satellite location that are focused at a first focal point and at least a second LNBF receives signals in a second frequency band transmitted from a second satellite location that are focused at a second focal point, wherein the boresight of the first LNBF is closer to the first focal point than the boresight of the second LNBF is to the second focal point.Type: GrantFiled: February 28, 2007Date of Patent: December 16, 2008Assignee: The DIRECTV Group, Inc.Inventors: Kesse Ho, John Norin, Ernest C. Chen, Joseph Santoru
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Patent number: 7467170Abstract: A method for generating a set of random numbers with statistics represented by a cumulative density function (CDF) includes generating a set of uniformly spaced samples between an upper limit and a lower limit. Each of the uniformly spaced samples are then mapped to a corresponding value on a cumulative density function curve. The set of uniformly spaced samples are then scrambled to randomize the samples. Companding may also be incorporated in the sample generation process.Type: GrantFiled: September 23, 2003Date of Patent: December 16, 2008Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Paul R. Anderson, Joseph Santoru, Tammy G. Liu
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Patent number: 7463676Abstract: A method and apparatus for measuring the phase noise of an low noise block (LNB) and other devices while the device under test is on line is disclosed. Using a signal processing procedure over a short duration of a received signal, the technique demodulates the signal to expose the phase history of the underlying carrier for measurement. In an exemplary apparatus timing and carrier recovery on A/D samples are performed conventionally, a linear phase is estimated from minimum mean square fitting to the recovered carrier phase history, the single tone carrier is removed from the recovered phase to yield a residual phase. A fast Fourier transform (FFT) can be performed on the residual phase to produce a phase noise spectral measurement at an input of the demodulator.Type: GrantFiled: October 24, 2003Date of Patent: December 9, 2008Assignee: The DIRECTV Group, Inc.Inventor: Ernest C. Chen
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Publication number: 20080298505Abstract: A method and receiver systems for demodulating and decoding a hierarchically modulated signal, e.g. an 8PSK signal, are disclosed. An exemplary method includes demodulating and processing (502) the hierarchically modulated signal (202) to produce symbols (212) from the first modulation at the first hierarchical level, applying information (504) from a plurality of the symbols from the first modulation at the first hierarchical level in subtracting (214) from the demodulated hierarchically modulated signal to obtain the second modulation at the second hierarchical level and processing (506) the second modulation at the second hierarchical level to produce second symbols (222) from the demodulated second signal. The hierarchically modulated signal comprises a non-uniform 8PSK signal. Applying the information from the plurality of the symbols from the first modulation can be achieved by applying the symbols after error correction.Type: ApplicationFiled: July 21, 2008Publication date: December 4, 2008Applicant: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Joseph Santoru
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Patent number: 7460832Abstract: Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises scrambling a first frame using a first scrambling code, attaching a first header to the first frame to create the first signal, scrambling a second frame using a second scrambling code, attaching a second header to the second frame to create the second signal, and transmitting the first signal and the second signal over different channels of the communication system.Type: GrantFiled: April 11, 2005Date of Patent: December 2, 2008Assignee: The DIRECTV Group, Inc.Inventors: Lin-Nan Lee, Feng-Wen Sun, Adam Von Ancken, Joseph Santoru, Ernest C. Chen, Shamik Maitra, Dennis Lai, Guangcai Zhou, Tung-Sheng Lin
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Patent number: 7426243Abstract: Systems and methods for receiving non-coherent layered modulation signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal, a processor for decoding the layered in-phase signal and the layered quadrature signal to produce a single layer in-phase signal and a single layer quadrature signal, a digital-to-analog encoder for converting the single layer in-phase signal and the single layer quadrature signal to a single layer in-phase analog signal and a single layer quadrature analog signal and a modulator for modulating the single layer in-phase analog signal and the single layer quadrature analog signal to produce a single layer signal.Type: GrantFiled: January 2, 2007Date of Patent: September 16, 2008Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, Joseph Santoru
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Patent number: 7426246Abstract: Systems and methods for receiving layered modulation for digital signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal and a processor for decoding the layered in-phase signal and the layered quadrature signal to produce one or more discrete layer signals.Type: GrantFiled: November 22, 2006Date of Patent: September 16, 2008Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, Joseph Santoru
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Patent number: 7423987Abstract: Systems and methods are disclosed for feeder link configurations to layered modulation. One feeder link system employs feeder link spot beam to antennas in distinct coverage areas to enable frequency reuse. Another system employs narrow beam width feeder link antenna to illuminate individual satellites also enabling frequency reuse. Yet another system uses layered modulation in the feeder link. Another feeder link system employs a higher order synchronous modulation for the satellite feeder link than is used in the layered modulation downlink signals.Type: GrantFiled: October 20, 2003Date of Patent: September 9, 2008Assignee: The DIRECTV Group, Inc.Inventors: Paul R. Anderson, Joseph Santoru, Ernest C. Chen
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Publication number: 20080209478Abstract: Multiple embodiments of systems for testing the delivery of satellite and cable television signals are described.Type: ApplicationFiled: February 18, 2008Publication date: August 28, 2008Applicant: THE DIRECTV GROUP, INC.Inventors: Joseph Santoru, David J. Kuether, Benjamin Mui, Shamik Maitra, Dipak M. Shah, Romulo Pontual, James R. Butterworth, Philip J. Goswitz, Ernest C. Chen, Gustave R. Stroes, Bradley T. Ito
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Patent number: 7418060Abstract: A method and receiver systems for demodulating and decoding a hierarchically modulated signal, e.g. an 8 PSK signal, are disclosed. An exemplary method includes demodulating and processing (502) the hierarchically modulated signal (202) to produce symbols (212) from the first modulation at the first hierarchical level, applying information (504) from a plurality of the symbols from the first modulation at the first hierarchical level in subtracting (214) from the demodulated hierarchically modulated signal to obtain the second modulation at the second hierarchical level and processing (506) the second modulation at the second hierarchical level to produce second symbols (222) from the demodulated second signal. The hierarchically modulated signal comprises a non-uniform 8 PSK signal. Applying the information from the plurality of the symbols from the first modulation can be achieved by applying the symbols after error correction.Type: GrantFiled: July 1, 2003Date of Patent: August 26, 2008Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Joseph Santoru
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Patent number: 7412209Abstract: Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises shifting a characteristic of the first signal with respect to a like characteristic of the second signal to mitigate co-channel interference, and transmitting the first signal and the second signal over different channels of the communication system.Type: GrantFiled: April 11, 2005Date of Patent: August 12, 2008Assignee: The DIRECTV Group, Inc.Inventors: Joseph Santoru, Ernest C. Chen, Shamik Maitra, Dennis Lai, Guangcai Zhou, Tung-Sheng Lin
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Publication number: 20080181291Abstract: Methods and apparatuses identifying a co-channel interference signal in communications systems are disclosed. An exemplary method comprises generating an interference signal by subtracting a reconstructed desired signal from an at least partially demodulated composite signal, and generating synchronization statistics of interference signal using different scrambling codes. The interference signal is identified as the signal associated with the scrambling code that was used to generate an interference signal having a desired synchronization statistic.Type: ApplicationFiled: April 4, 2008Publication date: July 31, 2008Applicant: THE DIRECTV GROUP, INC.Inventors: Guangcai Zhou, Ernest C. Chen, Joseph Santoru, Judith M. Wang
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Patent number: 7403574Abstract: A simplified scrambling scheme that unifies all signals of a satellite broadcasting system, including frame header (404), frame body (402) and pilot symbols (408) with a common reference phase. This results in the simplification and increased flexibility of the receiver front-end design without affecting the overall system performance. In many current communications systems with frame headers and pilot symbols, the phases of frame headers and pilot syrnbols are not designed to be aligned with any constellation points of the modulated data from the frame body. This scrambling scheme takes into account possible impact due to irregular phase changes between frame headers/pilot symbols and modulated data.Type: GrantFiled: August 27, 2004Date of Patent: July 22, 2008Assignee: The DIRECTV Group, Inc.Inventors: Ernest C. Chen, Dennis Lai, Tung-Sheng Lin, William C. Lindsey, Shamik Maitra, Joseph Santoru, Guangcai Zhou
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Publication number: 20080129374Abstract: Systems and methods for characterizing amplifiers. A system for characterizing an amplifier in accordance with the present invention comprises a Gaussian signal source for generating a signal in the frequency domain, a notch filter, coupled to the Gaussian Noise source, wherein the notch filter has a notch at a specified frequency and a frequency bandwidth, the frequency bandwidth encompassing the specified frequency, an Inverse Fast Fourier Transform device, coupled to an output of the notch filter, a normalization device, coupled to the Inverse Fast Fourier Transform device, an amplifier under test, coupled to the normalization device, for amplifying the signal generated by the Gaussian signal source, and a measurement device, coupled to an output of the amplifier, for measuring a power output of the amplifier in the frequency bandwidth and a noise output at the specified notch frequency, and for calculating the ratio between the power output and the noise output.Type: ApplicationFiled: October 11, 2007Publication date: June 5, 2008Applicant: THE DIRECTV GROUP, INC.Inventors: Guangcai Zhou, Tung-Sheng Lin, Dennis Lai, Joseph Santoru, Ernest C. Chen, Shamik Maitra, Cecilia Comeaux
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Publication number: 20080120654Abstract: A system 10 that includes a first satellite 14 at a first orbital slot B includes a first transponder 32 generating a first downlink signal at a first frequency and a second downlink signal at a second frequency. An outdoor unit 50 is directed toward the first satellite 14. The outdoor unit includes a support structure 80 and a reflector 64 coupled to the support structure 80 and reflecting the first downlink signal from a first satellite. A first reflector reflects the second downlink signal from the first satellite. A first feed 66 is coupled to the support structure and receives the first downlink signal. A reflector 72 having frequency selective surface 74 coupled to the support structure 80 reflects the second downlink signal and passes the first downlink signal therethrough. The second feed 70B is coupled to the support structure 80 and receives the second downlink signal reflected from the frequency selective surface 74.Type: ApplicationFiled: November 21, 2006Publication date: May 22, 2008Inventors: Gustave R. Stroes, Patrick J. Loner, Joseph Santoru, Ernest C. Chen, Navid Motamed
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Patent number: 7292547Abstract: A nodal division multiple access technique for multiple access to a communications channel such as a satellite transponder. The present invention provides multiple access into a communications channel where each accessing site utilizes one signal from a composite amplitude/phase digital signal constellation, such that demodulators receive the composite signal without changes in the system design related to the multiple access operation.Type: GrantFiled: May 22, 2002Date of Patent: November 6, 2007Assignee: The DIRECTV Group, Inc.Inventors: John P. Godwin, Ernest C. Chen