Patent application number | Description | Published |
20080291980 | CANCELLATION OF INTERFERENCE IN A COMMUNICATION SYSTEM WITH APPLICATION TO S-CDMA - Cancellation of interference in a communication system with application to S-CDMA. A relatively straight-forward implemented and computationally efficient approach of selecting a predetermined number of unused codes is used to perform weighted linear combination selectively with each of the input spread signals in a multiple access communication system. If desired, the predetermined number of unused codes is always the same in each implementation. Alternatively, the predetermined number of unused codes is selected from within a reordered code matrix using knowledge that is shared between the two ends of a communication system, such as between the CMs and a CMTS. While the context of an S-CDMA communication system having CMs and a CMTS is used, the solution is generally applicable to any communication system that seeks to cancel narrowband interference. Several embodiments are also described that show the generic applicability of the solution across a wide variety of systems. | 11-27-2008 |
20080298437 | CANCELLATION OF BURST NOISE IN A COMMUNICATION SYSTEM WITH APPLICATION TO S-CDMA - A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed. | 12-04-2008 |
20090103669 | Adaptive equalization and interference cancellation with time-varying noise and/or interference - A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. The noise analyzer produces a selection signal indicating the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of equalization coefficients and/or updates at least one parameter of a least-squares algorithm or the suitable equivalent algorithm to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of a particular time-varying noise and/or interference condition. In another exemplary embodiment, the communications receiver selects a corresponding adaptive equalizer from an adaptive equalizer bank to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of the particular time-varying noise and/or interference condition. | 04-23-2009 |
20090129484 | Low Density Parity Check (LDPC) Encoded Higher Order Modulation - A method and apparatus is disclosed to map a sequence of data to Quadrature Amplitude Modulation (QAM) constellation symbols. The method and apparatus encodes only a portion of the sequence of data and leaves a remaining portion of the sequence of data unencoded. The encoded portion of the sequence of data and the remaining unencoded portion of the sequence of data are then mapped into modulation symbols of the QAM constellation. The encoded portion of the sequence of data selects subsets of the QAM constellation, and the remaining unencoded portion of the sequence of data determines a specific modulation symbol within each subset of the QAM constellation. | 05-21-2009 |
20090161782 | Characterizing channel response based on composite gain determination - Characterizing channel response based on composite gain determination. Based on tracked amplitude modulation (e.g., which may be hum modulation), compensation for amplitude modulation is applied across all orthogonal signal components of a non-time based orthogonal coded signal. Some examples of such non-time based orthogonal coded signals include an orthogonal frequency division multiplexing (OFDM) signal, a synchronous code division multiple access (S-CDMA) signal, or a code division multiple access (CDMA) signal, etc. The compensation may be applied to the signal across multiple frames, on a frame by frame basis, or intra-frame (i.e., changing and compensating differently within a frame). This compensation for amplitude modulation may be applied in conjunction with adaptive equalization in which different filter taps are applied to each respective orthogonal signal component of the signal. Also, automatic gain control (AGC) may be performed (e.g., before digital sampling) of a received signal in conjunction with the amplitude modulation compensation. | 06-25-2009 |
20090215403 | Signal processing under attenuated transmission conditions - Signal processing under attenuated transmission conditions. Within an orthogonal signal space, the number of orthogonal signals that are used to transmit information from a transmitter to a receiver is reduced and the transmitted power of each of the now remaining orthogonal signals is modified; this may involve increasing the power of all of the remaining orthogonal signals equally or alternatively modifying them individually. The same modulation used before the reduction may also be used afterwards; within communication systems having multiple transmitter-receiver paths, this will ensure that the communication system's throughput and efficiency will remain unchanged even when one (or more) transmitter-receiver paths are highly attenuated. In addition, robust mode operation is provided for ranging and registering of transmitter devices when entering the communication system. In addition, the unused orthogonal signals may be employed to support interference cancellation of those orthogonal signals that are used to transmit information. | 08-27-2009 |
20090285343 | SYSTEM AND METHOD FOR CANCELING INTERFERENCE IN A COMMUNICATION SYSTEM - A filter settings generation operation includes sampling a communication channel to produce a sampled signal. The sampled signal is spectrally characterized across a frequency band of interest to produce a spectral characterization of the sampled signal. This spectral characterization may not include a signal of interest. The spectral characterization is then modified to produce a modified spectral characterization. Filter settings are then generated based upon the modified spectral characterization. Finally, the communication channel is filtered using the filter settings when the signal of interest is present on the communication channel. In modifying the spectral characterization, pluralities of spectral characteristics of the spectral characterization are independently modified to produce the modified spectral characterization. Modifications to the spectral characterization may be performed in the frequency domain and/or the time domain. One particular spectral modification that is performed is raising of the noise floor of the spectral characterization to meet a budgeted signal-to-noise ratio. Other spectral modifications include modifying spectral components corresponding to an expected interfering signal. In modifying these spectral characterizations, spectral components corresponding to a plurality of expected interfering signals may be modified. | 11-19-2009 |
20090327845 | System and Method For Mitigating Burst Noise In A Communications System - A system, method and computer program product is provided for mitigating the effects of burst noise on packets transmitted in a communications system. A transmitting device applies an outer code, which may include, for example, a block code, an exclusive OR (XOR) code, or a repetition code, to one or more packets prior to adaptation of the packets for transmission over the physical (PHY) layer of the communications system, wherein the PHY layer adaptation may include FEC encoding of individual packets. The outer coded packets are then separately transmitted over a channel of the communications system. A receiving device receives the outer coded packets, performs PHY level demodulation and optional FEC decoding of the packets, and then applies outer code decoding to the outer coded packets in order to restore packets that were erased during transmission due to burst noise or other impairments on the channel. | 12-31-2009 |
20100002760 | System and Method for Linear Distortion Estimation by Way of Equalizer Coefficients - Provided is a method and system for estimating distortion in a communications channel including an adaptive equalizer. The method includes determining one or more adaptive filter coefficients associated with a signal passed through the equalizer. The method also includes estimating un-equalized channel distortion based upon the determined adaptive filter coefficients. | 01-07-2010 |
20100052967 | Analog to digital converter (ADC) with extended dynamic input rang - A method and apparatus is disclosed to extend a dynamic input range of an analog to digital converter (ADC). A composite ADC may include one or more ADCs. The one or more ADCs compare a signal metric of an analog input signal to quantization levels to produce intermediate digital output signals using one or more non-clipping input values. The composite ADC may select among the one or more intermediate digital output signals based on the signal metric of the analog input signal to produce a final digital output. | 03-04-2010 |
20100111141 | Cancellation of burst noise in a communication system with application to S-CDMA - A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed. | 05-06-2010 |
20100180165 | SYSTEM AND METHOD OF UNCORRELATED CODE HOPPING IN A COMMUNICATIONS SYSTEM - A system and method are used to provide uncorrelated code hopping in a communications system. A shift register receives data. The shift register is clocked to shift the data. A scaler performs a scaling operation on the data with a numerical value of active codes. A truncator truncates the scaled data to its seven most significant bits to produce a pseudo random hop number. A code matrix shifter circularly shifts the active codes in a code matrix based on the pseudo random hop number to produce a circularly shifted code. A transmitter transmits the circularly shifted code. | 07-15-2010 |
20100202689 | VIDEO TELEPHONY IMAGE PROCESSING - Herein described is a system and method for modifying facial video transmitted from a first videophone to a second videophone during a videophone conversation. A videophone comprises a videophone image processing system (VIPS) that stores one or more preferred images. The one or more preferred images may comprise an image of a person presented in an attractive appearance. The one or more preferred images may comprise one or more avatars. Additionally, the VIPS may be used to incorporate one or more facial features of the person into a preferred image or avatar. Furthermore, a replacement background may be incorporated into the preferred image or avatar. The VIPS transmits a preferred image of a first speaker of a first videophone to a second speaker of a second videophone by capturing an actual image of the first speaker and substituting at least a portion of said actual image with a stored image. | 08-12-2010 |
20100215217 | Method and System of Tracking and Stabilizing an Image Transmitted Using Video Telephony - Herein described is a system and method that tracks the face of a person engaged in a videophone conversation. In addition to performing facial tracking, the invention provides stabilization of facial images that are transmitted during the videophone conversation. The face is tracked by employing one or more algorithms that correlate videophone captured facial images against a stored facial image. The face may be better identified by way of employing one or more voice recognition algorithms. The one or more voice recognition algorithms may correlate utterances of the person engaged in a conversation to one or more stored utterances. The identified utterances are subsequently mapped to a stored facial image. In a representative embodiment, the system used for performing facial tracking and image stabilization comprises an image sensor, a lens, an actuator, and a controller/processor. | 08-26-2010 |
20100272447 | Signal detection for optical transmitters in networks with optical combining - Signal detection for optical transmitters in networks with optical combining. Presented herein is a multi-faceted means for performing electrical to optical conversion such as in an optical transmitter as implemented within a communication system including at least some optical communication links therein. The turning on and turning off of a light source (e.g., a laser diode (LD), a light emitting diode (LED), and/or other component that performs electrical to optical conversion) is performed in accordance with a number of operational parameters. Some communication systems include multiple optical links (e.g., multiple fiber-optic links) from multiple transmitters that connect to a common receiver. In addition, some optical transmitters include multiple electrical links (e.g., multiple electrical communication links) from multiple communication devices that connect thereto. | 10-28-2010 |
20110021170 | Interference Cancellation with Time-Varying Interference and/or Distortion - A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. The noise analyzer may provide a selection signal indicating the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of filter coefficients to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of a particular time-varying interference and/or distortion condition. In another exemplary embodiment, the communications receiver selects a corresponding interference cancellation filter bank to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of the particular time-varying interference and/or distortion condition. | 01-27-2011 |
20110063148 | Imbalance and distortion cancellation for composite analog to digital converter (ADC) - Imbalance and distortion cancellation for composite analog to digital converter (ADC). Such an ‘ADC’ is implemented using two or more ADCs may be employed for sampling (e.g., quantizing, digitizing, etc.) of an analog (e.g., continuous time) signal in accordance with generating a digital (e.g., discrete time) signal. Using at least two ADCs allows for the accommodation and sampling of various signals having a much broader dynamic range without suffering degradation in signal to noise ratio (SNR). Generally, the signal provided via at least one of the paths corresponding to at least one of the respective ADCs is scaled (e.g., attenuated), so that the various ADCs effectively sample signals of different magnitudes. The ADCs may respectively correspond to different magnitude and/or power levels (e.g., high power, lower power, any intermediary power level, etc.). Various implementations of compensation may be performed along the various paths corresponding to the respective ADCs. | 03-17-2011 |
20110135044 | System and Method for Canceling Interference in a Communication System - A filter settings generation operation includes sampling a communication channel to produce a sampled signal. The sampled signal is spectrally characterized across a frequency band of interest to produce a spectral characterization of the sampled signal. This spectral characterization may not include a signal of interest. The spectral characterization is then modified to produce a modified spectral characterization. Filter settings are then generated based upon the modified spectral characterization. Finally, the communication channel is filtered using the filter settings when the signal of interest is present on the communication channel. In modifying the spectral characterization, pluralities of spectral characteristics of the spectral characterization are independently modified to produce the modified spectral characterization. Modifications to the spectral characterization may be performed in the frequency domain and/or the time domain. One particular spectral modification that is performed is raising of the noise floor of the spectral characterization to meet a budgeted signal-to-noise ratio. Other spectral modifications include modifying spectral components corresponding to an expected interfering signal. In modifying these spectral characterizations, spectral components corresponding to a plurality of expected interfering signals may be modified. | 06-09-2011 |
20110200091 | Asymmetric Multi-Channel Adaptive Equalizer - An apparatus is disclosed to compensate for non-linear effects resulting from the transmitter, the receiver, and/or the communication channel in a communication system. A receiver of the communication system contains an image cancellation module that compensates for images generated during the modulation and/or demodulation process. The image cancellation module includes a fine carrier correction loop to correct for frequency offsets between the transmitter and receiver. The image cancellation module includes a coarse acquisition mode and a decision directed mode. The decision directed mode allows for a larger signal-to-noise ratio for the receiver when compared against the coarse acquisition mode. | 08-18-2011 |
20110227768 | Imbalance and distortion cancellation for composite analog to digital converter (ADC) - Imbalance and distortion cancellation for composite analog to digital converter (ADC). Such an ‘ADC’ is implemented using two or more ADCs may be employed for sampling (e.g., quantizing, digitizing, etc.) of an analog (e.g., continuous time) signal in accordance with generating a digital (e.g., discrete time) signal. Using at least two ADCs allows for the accommodation and sampling of various signals having a much broader dynamic range without suffering degradation in signal to noise ratio (SNR). Generally, the signal provided via at least one of the paths corresponding to at least one of the respective ADCs is scaled (e.g., attenuated), so that the various ADCs effectively sample signals of different magnitudes. The ADCs may respectively correspond to different magnitude and/or power levels (e.g., high power, lower power, any intermediary power level, etc.). Various implementations of compensation may be performed along the various paths corresponding to the respective ADCs. | 09-22-2011 |
20110286473 | Signal processing under attenuated transmission conditions - Signal processing under attenuated transmission conditions. Within an orthogonal signal space, the number of orthogonal signals that are used to transmit information from a transmitter to a receiver is reduced and the transmitted power of each of the now remaining orthogonal signals is modified; this may involve increasing the power of all of the remaining orthogonal signals equally or alternatively modifying them individually. The same modulation used before the reduction may also be used afterwards; within communication systems having multiple transmitter-receiver paths, this will ensure that the communication system's throughput and efficiency will remain unchanged even when one (or more) transmitter-receiver paths are highly attenuated. In addition, robust mode operation is provided for ranging and registering of transmitter devices when entering the communication system. In addition, the unused orthogonal signals may be employed to support interference cancellation of those orthogonal signals that are used to transmit information. | 11-24-2011 |
20120076193 | System and Method for Linear Distortion Estimation By Way of Equalizer Coefficients - Provided is a method and system for estimating distortion in a communications channel including an adaptive equalizer. The method includes determining one or more adaptive filter coefficients associated with a signal passed through the equalizer. The method also includes estimating un-equalized channel distortion based upon the determined adaptive filter coefficients. | 03-29-2012 |
20120082272 | SELECTABLE INTERFERENCE CANCELLATION IN A COMMUNICATIONS RECEIVER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions. | 04-05-2012 |
20120082276 | COMPENSATING FOR UNWANTED INTERFERENCE IN A COMMUNICATIONS RECEIVER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions. | 04-05-2012 |
20120082277 | CONFIGURABLE ADAPTIVE FILTER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions. | 04-05-2012 |
20120082278 | COMPENSATING FOR UNWANTED INTERFERENCE IN A COMMUNICATIONS RECEIVER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions. | 04-05-2012 |
20120083235 | COMPENSATING FOR UNWANTED DISTORTION IN A COMMUNICATIONS RECEIVER - Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions. | 04-05-2012 |
20120106678 | METHOD AND APPARATUS TO IMPROVE ACQUISITION OF A QUADRATURE AMPLITUDE MODULATED (QAM) SIGNAL HAVING A FREQUENCY OFFSET - A method and apparatus are described that result in an improved acquisition of a received communication signal containing a large frequency offset. The method and apparatus raises a derotated sequence of data to a power of an integer provide a sinusoidal spectral component. The method and apparatus determines a cross product based upon the sinusoidal spectral component to provide a phase error. The method and apparatus determines an oscillator signal based upon the phase error. The method and apparatus adjusts the received communication signal based upon the oscillator signal to compensate for the large frequency offset to provide the derotated sequence of data. | 05-03-2012 |
20120182165 | Digital to analog converter (DAC) with ternary or tri-state current source - Digital to analog converter (DAC) with ternary or tri-state current source. A DAC including a number of ternary or tri-state devices operates based upon codewords provided thereto. Generally, each respective codeword bit directs operation of one of the respective ternary or tri-state devices within the DAC. Each ternary or tri-state device operates in at least three respective operational states (e.g., based upon the respective values of +1, −1, or 0 being provided thereto). In a current source implementation, each respective current source is implemented to deliver current, draw current, or neither delivered or draw current. In a voltage source implementation, each respective voltage source is implemented to provide a positive voltage, a negative voltage, or provide no voltage. A DAC coding table may be designed based upon characterization of codewords provided to one or more DACs (e.g., based upon a distribution, a probability density function (PDF), etc. of such codewords). | 07-19-2012 |
20120183027 | Dual digital to analog converters (DACs) with codeword parsing - Dual digital to analog converters (DACs) with codeword parsing. With respect to a codeword that is provided to a DAC, a processing module (e.g., a rollover processor) operates to divide, partition, etc. the codeword into different respective sub-codewords as may be provided to two or more DAC's. Adaptation with respect to differently generated sub-codewords with respect to different respective codewords may be made in terms of any one or more of a variety of characteristics, including sub-codeword width (e.g., the number of bits included within a sub-codeword), quantization steps, etc. Moreover, such adaptation may be in consideration of any one or more local and/or remote operating characteristics of one or more devices, communication links, etc. within a communication system or network. Different respective sub-codewords undergo processing by different respective DAC's in generating respective analog signals for combination in generating a final or output analog signal. | 07-19-2012 |
20120183031 | Distortion and aliasing reduction for digital to analog conversion - Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion. | 07-19-2012 |
20120183082 | Distortion and aliasing reduction for digital to analog conversion - Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion. | 07-19-2012 |
20120183110 | Distortion and aliasing reduction for digital to analog conversion - Distortion and aliasing reduction for digital to analog conversion. Synthesis of one or more distortion terms made based on a digital signal (e.g., one or more digital codewords) is performed in accordance with digital to analog conversion. The one or more distortion terms may correspond to aliased higher-order harmonics, distortion, nonlinearities, clipping, etc. Such distortion terms may be known a priori, such as based upon particular characteristics of a given device, operational history, etc. Alternatively, such distortion terms may be determined based upon operation of a device and/or based upon an analog signal generated from the analog to conversion process. For example, frequency selective measurements made based on an analog signal generated from the digital to analog conversion may be used for determination of and/or adaptation of the one or more distortion terms. One or more DACs may be employed within various architectures operative to perform digital to analog conversion. | 07-19-2012 |
20120189046 | Asymmetric Multi-Channel Adaptive Equalizer - An apparatus is disclosed to compensate for non-linear effects resulting from the transmitter, the receiver, and/or the communication channel in a communication system. A receiver of the communication system contains an image cancellation module that compensates for images generated during the modulation and/or demodulation process. The image cancellation module includes a fine carrier correction loop to correct for frequency offsets between the transmitter and receiver. The image cancellation module includes a coarse acquisition mode and a decision directed mode. The decision directed mode allows for a larger signal-to-noise ratio for the receiver when compared against the coarse acquisition mode. | 07-26-2012 |
20120196551 | COMMUNICATION RECEIVER ENHANCEMENTS USING MULTI-SIGNAL CAPTURE - A method and apparatus is disclosed to determine communications receiver parameters from multiple channels of a received communications signal and to configure and/or adjust communications receiver parameters to acquire one or more channels from among the multiple channels of the received communications signal. A communications receiver observes a multi-channel communication signal as it passes through a communication channel. The communications receiver determines one or more communications receiver parameters from the multiple channels of the received communications signal. The communications receiver configures and/or adjusts communications receiver parameters to acquire the one or more channels from among the multiple channels of the received communications signal. | 08-02-2012 |
20120201288 | Adaptive Equalization and Interference Cancellation with Time-Varying Noise and/or Interference - A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or the distortion and produce a selection signal indicating the composition of the interference and/or the distortion. The communications receiver selects at least one set of equalization coefficients and/or updates at least one parameter of a least-squares algorithm or the suitable equivalent algorithm to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of a particular time-varying noise and/or interference condition. | 08-09-2012 |
20120235841 | DIGITAL CORRECTION TECHNIQUES FOR DATA CONVERTERS - A method and apparatus is disclosed to compensate for impairments within a data converter such that its output is a more accurate representation of its input. The data converter includes a main data converter, a reference data converter, and a correction module. The main data converter may be characterized as having the impairments. As a result, the output of the main data converter is not the most accurate representation of its input. The reference data converter is designed such that the impairments are not present. The correction module estimates the impairments present within the main data converter using its output and the reference data converter to generate corrections coefficients. The correction module adjusts the output of the main data converter using the corrections coefficients to improve the performance of the data converter. | 09-20-2012 |
20130010897 | Low Density Parity Check (LDPC) Encoded Higher Order Modulation - A method and apparatus is disclosed to map a sequence of data to Quadrature Amplitude Modulation (QAM) constellation symbols. The method and apparatus encodes only a portion of the sequence of data and leaves a remaining portion of the sequence of data unencoded. The encoded portion of the sequence of data and the remaining unencoded portion of the sequence of data are then mapped into modulation symbols of the QAM constellation. The encoded portion of the sequence of data selects subsets of the QAM constellation, and the remaining unencoded portion of the sequence of data determines a specific modulation symbol within each subset of the QAM constellation. | 01-10-2013 |
20130085703 | Histogram-Based Linearization of Analog-to-Digital Converters - Embodiments provide histogram-based methods and system to estimate the transfer function of an ADC, and subsequently to linearize a non-linear ADC transfer function. Embodiments include blind algorithms that require no a priori knowledge of the input signal distribution. Embodiments can be implemented using cumulative (i.e., cumulative distribution function (CDF)) or non-cumulative (i.e., probability density function (PDF)) histograms. According to embodiments, a non-linear transfer function can be estimated by linearly approximating successive local intervals of the transfer function. Linearly approximated successive local intervals of the transfer function can then be used to fully characterize and closely estimate the transfer function. | 04-04-2013 |
20130279557 | Interference Cancellation with Time-Varying Interference and/or Distortion - A communications receiver includes a noise analyzer to characterize the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. The noise analyzer may provide a selection signal indicating the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of filter coefficients to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of a particular time-varying interference and/or distortion condition. In another exemplary embodiment, the communications receiver selects a corresponding interference cancellation filter hank to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of the particular time-varying interference and/or distortion condition. | 10-24-2013 |
20140181611 | System and Method for Mitigating Burst Noise in a Communications System - A system, method and computer program product is provided for mitigating the effects of burst noise on packets transmitted in a communications system. A transmitting device applies an outer code, which may include, for example, a block code, an exclusive OR (XOR) code, or a repetition code, to one or more packets prior to adaptation of the packets for transmission over the physical (PHY) layer of the communications system, wherein the PHY layer adaptation may include FEC encoding of individual packets. The outer coded packets are then separately transmitted over a channel of the communications system. A receiving device receives the outer coded packets, performs PHY level demodulation and optional FEC decoding of the packets, and then applies outer code decoding to the outer coded packets in order to restore packets that were erased during transmission due to burst noise or other impairments on the channel. | 06-26-2014 |