Patent application number | Description | Published |
20080232440 | CHIP BLANKING AND PROCESSING IN SCDMA TO MITIGATE IMPULSE AND BURST NOISE AND/OR DISTORTION - A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication. | 09-25-2008 |
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 |
20090122846 | ENHANCED CHANNEL CHANGING WITHIN MULTI-CHANNEL COMMUNICATION SYSTEMS - Enhanced channel changing within multi-channel communication systems. A CMTS directs channel changing of a CM, sometimes between upstream data bursts. Logical channels, part of a single frequency channel, may be used, and the channel changing may be performed between those logical channels. Multiple upstream burst profiles and/or modulation densities may be used providing high degrees of robustness, fidelity, and throughput and allowing great channel flexibility. A CM may be switched between channels without losing transmitter capability. Even if some throughput rate may be sacrificed during the channel changing, the CM will still be able to continue data throughput. Then, the new channel may then undergo the initialization and ranging processes thereby enabling greater throughput on that new channel. After undergoing the initialization and ranging processes, the new channel will then be a fully equivalent member of the CM communication system. | 05-14-2009 |
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 |
20090161781 | Characterizing channel response using data tone decision feedback - Characterizing channel response using data tone decision feedback. In addition, to pilot tones which may be existent within an orthogonal frequency division multiplexing (OFDM) signal, one or more date tones within that same signal may be employed to assist with channel estimation (alternatively, detection). Once a data tone qualifies as a pseudo-pilot tone, it may be used with the pilot tones for channel estimation. A qualifier considers slicer error associated with hard decisions for a data tone to determine if it is a candidate for assistance within channel estimation. A frame within an OFDM signal may, in one situation, include no pilot tones at all, and a previously calculated channel estimate may be used to process that frame. In addition, fewer pilot tones than needed to perform accurate channel estimation (based on the channel delay spread) may be employed by using one or more pseudo-pilot tones (e.g., qualified data tones). | 06-25-2009 |
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 |
20090204772 | Memory depth optimization in communications systems with ensemble PHY layer requirements - Memory depth optimization in communications systems with ensemble PHY layer requirements. Memory depth, for one or more modules in a communication device, is managed based on a limited amount of provisioned hardware. For example, each of a number of various modules within a communication device is configurable to operate at various memory depths. Considered together, various sets or profiles of operational parameters (e.g., associated with particular settings for each of the various modules within the communication device), may be employed to configure the communication device to operate in accordance with one of a variety of operational modes. For example, in a first operational mode, latency may be minimized (e.g., using shorted codewords, shorter interleaver depth, etc.), whereas in a second operational mode, a higher latency may be tolerated but with an expectation of much lower error rates (e.g., achieved using more powerful ECC, longer interleaver depth, etc.). | 08-13-2009 |
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 |
20090296664 | Detection and Mitigation of Temporary (Bursts) Impairments in Channels Using SCDMA - Systems and methods are disclosed for detecting and mitigating temporary high-level impairments, in a communications channel, and subsequently, mitigating the deleterious effects of the dynamic impairments. The system includes a transmitter and a receiver. The transmitter is adapted to transmit at least one set of modulated signals. The receiver is adapted to receive the at least one set of modulated signals and mitigate temporary high-level impairment in the at least one set of modulated signals using at least one error vector received during the temporary high-level impairment. | 12-03-2009 |
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 |
20100034220 | Successive interference canceling for CDMA - Successive interference canceling for CDMA. ICI may result from a signal's multi-path effects, or by filtering/suppression of some of the component energy of the signaling waveforms. Energy component attenuation destroys orthogonality of CDMA symbols thereby causing ICI. An ICF suppresses frequency domain portions (attenuates ingress), but also introduces ICI. Following the ICF, the signal is de-spread, sliced, re-spread and convolved with the ICF echoes (except first tap echoes). Convolving re-spread hard decisions with delayed ICF taps is equivalent to partially re-modulating the first-pass hard decisions to efficiently “add-back-in” the signal energy which was blanked/subtracted by the ICF. Alternatively, parameter estimation de-rotates and re-rotates soft symbols and hard decisions, respectively, compensating for undesirable symbol rotation. The convolved signal is subtracted from a delayed version of the ICF output signal. If desired, this process may be repeated successively to enhance the accuracy of the obtained data decisions in the next stage. | 02-11-2010 |
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 |
20100131824 | Handling burst error events with interleaved Reed-Solomon (RS) codes - Handling burst error events with interleaved Reed-Solomon (RS) codes. A received signal, that has undergone convolutional interleaving sometime before, is received from a burst noise affected communication channel. The signal undergoes convolutional deinterleaving and the codewords generated there from undergo appropriate successive cyclic shifting to arrange burst noise affected symbols of various codewords into at least some common symbol locations. For example, at least two codewords have burst noise affected symbols in common symbol locations. An ensemble decoder jointly decodes multiple codewords during a same time period (i.e., processes multiple codewords simultaneously). By processing multiple codewords simultaneously, the ensemble decoder has greater error correction capability than a decoder that processes a single codeword at a time. | 05-27-2010 |
20100142553 | Flexible Upstream PHY Burst Profile Parameters to Improve Performance of Short Bursts in Impulse Noise - A single carrier cable modem can be initialized on multiple channels. By initializing a cable modem on more than one channel, the error rate performance of short data packets in cable modems in an impulsive noise environment is improved. The advantage of low symbol rate transmission for short packets in an impulse noise environment is achieved without sacrificing burst capacity at a cable modem and without the complexity of transmitting multiple symbol waveforms simultaneously at a cable modem. | 06-10-2010 |
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 |
20100229075 | CHIP BLANKING AND PROCESSING IN SCDMA TO MITIGATE IMPULSE AND BURST NOISE AND/OR DISTORTION - A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication. | 09-09-2010 |
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 |
20110022925 | Turbo Coding for Upstream and Downstream Transmission in Cable Systems - A method of transmitting data in a cable modem system includes the steps of encoding the data using forward error correction. The data is then encoded with Turbo encoding. The data is then sent to a modulation scheme. The data is then transmitted over a cable channel. The data is then demodulated. The data is then decoded using a Turbo decoder. An inverse of the forward error correction is then applied to the data. | 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 |
20110072330 | Modified error distance decoding - Modified error distance decoding. In certain communication systems, multiple signals (e.g., which may be viewed as being codewords, groups/sets of bits or symbols, etc.) can be commonly affected by such deleterious phenomenon as burst noise when traversing a communication channel (e.g., from a transmitter communication device to a receiver communication device). In such instances, a test error pattern may be identified which covers those affected bits (or symbols) among at least two respective signals (e.g., all of the respective signals or any subset thereof). Various respective test error patterns may be employed, each having a different respective weight, to the desired group of signals (e.g., codewords, groups/sets of bits or symbols, etc.). As such, more than one possible estimate of each respective signal may be generated. A variety of selection operations may be employed when more than one possible estimate exists (e.g., random selection, that estimate with minimum distance, etc.). | 03-24-2011 |
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 |
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 |
20120106573 | Flexible Upstream PHY Burst Profile Parameters to Improve Performance of Short Bursts in Impulse Noise - A single carrier cable modem can be initialized on multiple channels. By initializing a cable modern on more than one channel, the error rate performance of short data packets in cable modems in an impulsive noise environment is improved. The advantage of low symbol rate transmission for short packets in an impulse noise environment is achieved without sacrificing burst capacity at a cable modem and without the complexity of transmitting multiple symbol waveforms simultaneously at a cable modem. | 05-03-2012 |
20120127962 | DETECTION AND MITIGATION OF TEMPORARY (BURSTS) IMPAIRMENTS IN CHANNELS USING SCDMA - Systems and methods are disclosed for detecting and mitigating temporary high-level impairments, in a communications channel, and subsequently, mitigating the deleterious effects of the dynamic impairments. The system includes a transmitter and a receiver. The transmitter is adapted to transmit at least one set of modulated signals. The receiver is adapted to receive the at least one set of modulated signals and mitigate temporary high-level impairment in the at least one set of modulated signals using at least one error vector received during the temporary high-level impairment. | 05-24-2012 |
20120182162 | Rollover operative digital to analog converter (DAC) - Rollover operative digital to analog converter (DAC). With respect to a codeword that is provided to a DAC, a processing module (e.g., a rollover processor) operates to compare the codeword to threshold(s) in accordance with adaptively partitioning the codeword into one or more sub-codewords when the codeword has a magnitude greater than at least one of the thresholds. In instances that the codeword is less than a threshold, the codeword may be provided directly to a DAC for use in generating a first analog signal. However, if the codeword is a larger than a threshold, then that portion of the codeword which is greater than the threshold may be provided to an alternative component such as one or more auxiliary or additional DACs, one or more other circuitry components, etc. in accordance with generating at least one additional analog signal to be combined with the first analog signal. | 07-19-2012 |
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 |
20120183083 | 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 |
20120230374 | Chip blanking and processing in SCDMA to mitigate impulse and burst noise and/or distortion - A system for mitigating impairment in a communication system includes a delay block, a signal level block, a moving average window block, an impulse noise detection block, and a combiner. The delay block receives and delays each chip of a plurality of chips in a spreading interval. The signal level block determines a signal level of each chip of the plurality of chips in the spreading interval. The moving average window block determines a composite signal level for a chip window corresponding to the chip. The impulse noise detection block receives the signal level, receives the composite signal level, and produces an erasure indication for each chip of the plurality of chips of the corresponding chip window. The combiner erases chips of the plurality of chips of the spreading interval based upon the erasure indication. | 09-13-2012 |
20120230383 | Linear distortion and interference estimation using decision feedback equalizer coefficients - Linear distortion and interference estimation using decision feedback equalizer coefficients. Processing of different respective groups of equalizer coefficients may be made to determine the residual frequency response of an equalizer and/or device in which the equalizer is implemented. Such an equalizer may be in woman within any of a number of respective communication devices including those operative within satellite, wireless, wired, fiber-optic, and/or mobile communication systems. A first group of equalizer coefficients corresponds to certain filtering characteristics of the equalizer and/or device in which the equalizer is implemented. The equalizer is implemented to process a signal to generate a second group of equalizer coefficients. Processing and/or analysis of the first group of equalizer coefficients and the second group of equalizer coefficients will generate a third group of equalizer coefficients corresponding to the residual frequency response of the equalizer and/or device in which the equalizer is implemented. | 09-13-2012 |
20120230385 | Narrowband ingress estimation and characterization using equalizer taps - Narrowband ingress estimation and characterization using equalizer taps. A equalizer including a feed forward equalizer (FFE) and a decision feedback equalizer (DFE) is implemented to process an input signal thereby generating an output signal. Analysis of the frequency response of the equalizer including the FFE and the DFE of the equalizer allows for the determination of whether or not narrowband ingress exists within the signal received by the equalizer. For example, analysis of the signal output from the equalizer provides for determination of the overall frequency response of the equalizer. In addition, analysis of the respective equalizer coefficients within one or both of the FFE and the DFE of the equalizer may be used to determine the overall frequency response of the equalizer. Narrowband ingress may be identified when the combination of the FFE (having a notch therein) and the DFE provides for an overall flat frequency response. | 09-13-2012 |
20120243527 | Upstream burst noise measurement and characterization - Upstream burst noise measurement and characterization. One or more communication devices is implemented to detect and measure burst noise event(s) within channel(s) associated with communication link(s) within communication system(s) or network(s). Detection and measurement of a burst noise event may be made during active communications on one or more other channels, and may be made during active communications on two channels respectively adjacent to the channel on which the burst noise event is being detected and measured. The channel on which the burst noise event is detected and measured may be an unused channel. The detection and measurement of the burst noise event may be made during a quiet time slot within one of the channels. Correlation (e.g., with respect time) may be determined with respect to different respective layers within a communication device (e.g., with respect to MAC and PHY layers). | 09-27-2012 |
20120243597 | Upstream frequency response measurement and characterization - Upstream frequency response measurement and characterization. Signaling is provided between respective communication devices within a communication system. Based upon at least one of these signals, one of the communication devices captures a number of sample sets corresponding thereto at different respective frequencies (e.g., a different respective center frequencies, frequency bands, etc.). Then, spectral analysis is performed with respect to each of the sample sets to generate a respective and corresponding channel response estimate there from. After this number of channel response estimates is determined, they are combined or splice together to generate a full channel response estimate. In implementations including an equalizer, different respective sample sets may correspond to those that have undergone equalization processing and those that have not. | 09-27-2012 |
20120243648 | Characterization and assessment of communication channel average group delay variation - Characterization and assessment of communication channel average group delay variation. A signal having repeated signal components therein is received by a communication device, and that signal undergoes appropriate processing to determine respective amplitude and phase of a number of frequency bins. The phase difference from bin to bin (including respecting unwrapping, and proper normalization) is used to determine the group delay of a communication channel, or portion thereof, as a function of frequency. Multiple respective group delay measurements may be averaged to generate a wideband group delay of the communication channel as a function of frequency. Overlap between different respective band-edge portions of the communication channel may assist in generating a seamless continuous wideband spectrum estimation for use in determining the wideband group delay of the communication channel. | 09-27-2012 |
20120243865 | Detection and characterization of laser clipping within communication devices - Detection and characterization of laser clipping within communication devices. Identification of one or more harmonics associated with a fundamental frequency by which signaling is effectuated within the communication system for laser clipping identification. Appropriate spectral signal analysis is made to identify the presence of characteristic(s) (e.g., energy, amplitude, phase, and/or other characteristic(s)), if any, at one or more harmonic frequencies within a received signal. Appropriate time correlation is performed to distinguish whether or not characteristic(s) associated with at one or more of these harmonic bands is a result of laser clipping or from some other source (e.g., such as other signals within a communication system that happened to reside at those respective harmonic bands). Such appropriate identified correlation between characteristic(s) corresponding to a fundamental frequency band of the communication signal and characteristic(s) corresponding to one or more harmonics (e.g., of that fundamental frequency band) indicates laser clipping. | 09-27-2012 |
20120281789 | Characterizing channel response using data tone decision feedback - In addition, to pilot tones which may be existent within an orthogonal frequency division multiplexing (OFDM) signal, one or more data tones within that same signal may be employed to assist with channel estimation (alternatively, detection). Once a data tone qualifies as a pseudo-pilot tone, it may be used with the pilot tones for channel estimation. A qualifier considers slicer error associated with hard decisions for a data tone to determine if it is a candidate for assistance within channel estimation. A frame within an OFDM signal may, in one situation, include no pilot tones at all, and a previously calculated channel estimate may be used to process that frame. In addition, fewer pilot tones than needed to perform accurate channel estimation (based on the channel delay spread) may be employed by using one or more pseudo-pilot tones (e.g., qualified data tones). | 11-08-2012 |
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 |
20130064323 | Turbo Coding for Upstream and Downstream Transmission in Cable Systems - A method of transmitting data in a cable modem system includes the steps of encoding the data using forward error correction. The data is then encoded with Turbo encoding. The data is then sent to a modulation scheme. The data is then transmitted over a cable channel. The data is then demodulated. The data is then decoded using a Turbo decoder. An inverse of the forward error correction is then applied to the data. | 03-14-2013 |
20130136142 | SYSTEMS AND METHODS TO TRANSMIT INFORMATION AMONG A PLURALITY OF PHYSICAL UPSTREAM CHANNELS - A communication system includes a supervisory node (e.g., a headend) and one or more remote nodes (e.g., cable modems). The supervisory node or a remote node monitors a characteristic associated with the communication system. Remote node transmits an upstream communication among a plurality of physical upstream channels based on the characteristic. The average transmit power used to transmit the upstream communication among the plurality of physical upstream channels is no greater than the average transmit power that would be necessary to transmit the upstream communication using a single physical upstream channel at a lower data rate. | 05-30-2013 |
20130215953 | Measurement of intermodulation products of digital signals - Measurement of intermodulation products of digital signals. One or more devices, within a communication system, having and analog to digital converter (ADC) with a sufficiently wide frequency response as to capture not only a signal of interest, but many other signals simultaneously, allows for appropriate signal processing of such captured samples to identify one or more intermodulation products that may exist as a function of the relationship of one or more frequencies. For example, composite second order (CSO) or composite triple beat (CTB), or even higher ordered signals, may occur within various communication systems. These effects may be caused by any of a number of sources including nonlinearities in the system, such as affects associated with laser clipping, amplifier compression, corroded connectors, etc. Appropriate processing is performed determine the existences of such intermodulation product signals, and, if desired, subsequent signal processing and/or fixing of such effects therein is performed. | 08-22-2013 |
20130219243 | Handling burst error events with interleaved Reed-Solomon (RS) codes - Handling burst error events with interleaved Reed-Solomon (RS) codes. A received signal, that has undergone convolutional interleaving sometime before, is received from a burst noise affected communication channel. The signal undergoes convolutional deinterleaving and the codewords generated there from undergo appropriate successive cyclic shifting to arrange burst noise affected symbols of various codewords into at least some common symbol locations. For example, at least two codewords have burst noise affected symbols in common symbol locations. An ensemble decoder jointly decodes multiple codewords during a same time period (i.e., processes multiple codewords simultaneously). By processing multiple codewords simultaneously, the ensemble decoder has greater error correction capability than a decoder that processes a single codeword at a time. | 08-22-2013 |
20130222161 | 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. | 08-29-2013 |
20130223506 | Flexible adaptive equalizer - Flexible adaptive equalizer. Communications may be supported between two or more respective devices within a communications system via one or more available channels. Such channels may be different respective communication channels or may be logical partitions of a given communication channel. Appropriate adaptation and provision of resources within one or more devices within the system may be performed based upon any of a number of characteristics and/or considerations associated with one or more devices, channels, etc. within the system. A number of equalizer elements may be employed to perform processing of respective signal(s) received via respective channel(s). Adaptation of which equalizer elements are employed for the respective channels may be modified, adapted, etc. over time based upon any of such number of characteristics and/or considerations. Also, a number of pre-equalizer elements may also be employed to perform processing of signal(s) to be transmitted via respective channel(s). | 08-29-2013 |
20130230130 | 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. | 09-05-2013 |
20130239164 | Method and system for Digital Video Broadcast for Cable (DVB-C2) - Methods and systems for DVB-C2 are disclosed and may include receiving data encoded utilizing variable encoding, variable modulation and outer codes via a physical layer matched to a desired quality of service. An error probability may be determined for said received data and retransmission of portions of said data with error probability above an error threshold may be requested. The variable modulation may include single carrier modulation, orthogonal frequency division modulation, synchronous code division multiple access, and/or from 256 QAM to 2048 QAM or greater. The variable encoding may include forward error correction code, which may include low density parity check code. | 09-12-2013 |
20130251019 | Sparse equalizer system - Sparse equalizer system. One or more multiple tapped delay lines (e.g., equalizers and/or pre-equalizers) are implemented to service one or more respective channels with which a communication device operates to support communications with at least one other communication device. Adaptive selection of which subsets of taps of the one or more multiple tapped delay lines is made to control those particular taps of which contribute to one or more subsequent slicer inputs. Those taps which are not currently operating to contribute to the slicer input may undergo processing, updating, etc. in parallel with or simultaneously with the processing of a signal to generate the outputs to be provided to the one or more subsequent slicers. | 09-26-2013 |
20130251063 | Concatenated coding scheme for burst noise and AWGN for multi-channel applications - Concatenated coding scheme for burst noise and AWGN for multi-channel applications. An appropriately selected and relatively powerful error correction code (ECC) or forward error correction (FEC) code is used as an inner code to cover two or more respective channels that have respectively undergone processing in accordance with an outer code. An input signal stream may undergo partitioning into a number of respective channels (e.g., sub-carriers of orthogonal frequency division multiplexing (OFDM) signaling (or different respective blocks or groups of OFDM subcarriers), different respective spreading codes of code division multiple access (CDMA) modulation, etc., or elements of any type of orthogonal signaling scheme) such that those respective channels undergo outer code processing to generate a number of coded signals, and subsequent inner code processing covers two or more of those respective coded signals. Such outer code processing may cover all of the coded signals provided by the inner code processing. | 09-26-2013 |
20130286855 | Spectrum analysis capability in network and/or system communication devices - Spectrum analysis (SA) capability is included in various communication devices within a communication network. One or more of the devices use the SA information from other devices in the system to determine status of various communication links were devices in the system. One or more processors within one or more devices can identify any actual/existing or expected failure or degradation of the various components within the system. Such components may include communication devices, communication channels or links, interfaces, interconnections, etc. When an actual/existing or expected failure or degradation is identified, the affected components may be serviced or devices within the system may operate to mitigate any reduction in performance caused by such problems. Such SA functionality/capability may be implemented in one communication device or in a distributed manner across a number of devices in a communication system. | 10-31-2013 |
20140003545 | Signal processing under attenuated transmission conditions | 01-02-2014 |
20140003552 | SET-PARTITIONED CODED MODULATION WITH INNER AND OUTER CODING | 01-02-2014 |
20140003560 | STAGGERED TRANSMISSION AND RECEPTION FOR REDUCING LATENCY AND MEMORY | 01-02-2014 |
20140079103 | Interference cancellation within OFDM communications - Many communication systems operate based on orthogonal frequency division multiplexing (OFDM) signaling and/or orthogonal frequency division multiple access (OFDMA) signaling. Within such systems, narrowband interference, which may alternatively be referred to as narrowband ingress, narrowband ingress interference, narrowband noise, etc., may adversely affect one or more subcarriers or tones causing a reduction in performance or even link failure. Such narrowband interference may affect only one or a relatively few tones employed within such communications. When the narrowband interference is identified, a transmission may then be made including one or more information-free tones. A device that receives such a transmission then uses those information-free tones to reduce or cancel the narrowband interference. Such processing may be performed in the frequency-domain, the time domain, or both. | 03-20-2014 |
20140086128 | Power savings within communication systems - A communication device is implemented to perform signal processing based on different dynamic ranges at different times. The device can operate with a first, relatively larger dynamic range during normal operations, and with a second, relatively smaller dynamic range during reduced power or sleep mode operations. The relatively smaller dynamic range may have a relatively higher noise floor than the larger dynamic range. Generally, any desired number of different dynamic ranges may be used at different times and based on different operating conditions. The communication device can include functionality associated with two or more transceivers to support communications based on two or more power modes (e.g., a full power mode, a reduced power mode or a sleep mode, etc.). The communication device may alternatively include two or more separate transceivers to support such communications. An unused transceiver or transceiver functionality may be turned off to provide power savings. | 03-27-2014 |
20140126345 | Simplified multi-modulation coding set (MCS) or multiple profile transmission (MPT) scheme for communications - A communication device includes a media access control (MAC) and a physical layer (PHY) processor and supports multi-profile communications with one or more other communication devices. The PHY processor selects a profile based on one or more characteristics of a communication pathway between the device and the one or more other communication devices. A profile may include operational parameters such as modulation coding set (MCS), forward error correction (FEC) and/or error correction code (ECC), a number of bits per symbol per sub-carrier and/or sub-carrier mapping (e.g., such as based on orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA)), cyclic prefix, channel(s) used in transmission, bit-filling and shortening, unicast and/or multicast transmission, and/or other operational parameters. The PHY processor also may be configured to operate within at least two different operational modes including a first mode of packet aggregation and a second mode of bit-filling and shortening. | 05-08-2014 |
20140169424 | Orthogonal frequency division multiplexing (OFDM) interleaving - A communication device is configured to perform interleaving of a modulation symbol sequence to generate an OFDM symbol. Some modulation symbols within the modulation symbol sequence that are separated by an interleaver depth may be transmitted via adjacently located sub-carriers, while other modulation symbols within the modulation sequence that are separated by more than the interleaver depth may also be transmitted via adjacently located sub-carriers. First adjacently located sub-carriers transmit first and second modulation symbols that are separated by the interleaver depth within the modulation sequence while second adjacently located sub-carriers transmit third and fourth modulation symbol that are separated by more than the interleaver depth within the modulation sequence. A communication device may be configured to adapt and switch between different operational parameters used for interleaving and/or deinterleaving at different times based on any desired considerations. | 06-19-2014 |
20140169425 | Orthogonal frequency division multiplexing (OFDM) with variable bit loading and time and/or frequency interleaving - A communication device is configured to perform processing of one or more bits to generate a modulation symbol sequence based on one or more profiles that specify variable bit loading of bits per symbol over at least some of the modulation symbols of the modulation symbol sequence. The communication device is also configured to perform interleaving of the modulation symbol sequence to generate OFDM symbol(s). Some modulation symbols within the modulation symbol sequence that are separated by an interleaver depth may be transmitted via adjacently located sub-carriers, while other modulation symbols within the modulation sequence that are separated by more than the interleaver depth may also be transmitted via adjacently located sub-carriers. A communication device may be configured to adapt and switch between different operational parameters used for bit loading, interleaving and/or deinterleaving at different times based on any desired considerations. | 06-19-2014 |
20140177750 | Fine step blended modulation communications - A communication device is configured to perform symbol mapping of bits to generate modulation symbols using one or more modulations. The device may employ a blended modulation composed of bit labels or symbols having different numbers of bits per symbol and different modulations. For example, the device may symbol map bit labels/symbols having first number of bits per symbol to first modulation, and the device may symbol map labels/symbols having second number of bits per symbol to second modulation. The device may be configured to perform forward error correction (FEC) or error correction code (ECC) and coding of information bits to generate coded bits that subsequently undergo symbol mapping. The device may be configured to operate based on different operational modes based on substantially uniform steps of rates, or bits per symbol, and energy per bit or symbol to noise spectral density ratio (E | 06-26-2014 |
20140334500 | SYSTEMS AND METHODS TO TRANSMIT INFORMATION AMONG A PLURALITY OF PHYSICAL UPSTREAM CHANNELS - A communication system includes a supervisory node (e.g., a headend) and one or more remote nodes (e.g., cable modems). The supervisory node or a remote node monitors a characteristic associated with the communication system. Remote node transmits an upstream communication among a plurality of physical upstream channels based on the characteristic. The average transmit power used to transmit the upstream communication among the plurality of physical upstream channels is no greater than the average transmit power that would be necessary to transmit the upstream communication using a single physical upstream channel at a lower data rate. | 11-13-2014 |
20150078194 | Spectrum analysis capability in network and/or system communication devices - Spectrum analysis (SA) capability is included in various communication devices within a communication network. One or more of the devices use the SA information from other devices in the system to determine status of various communication links were devices in the system. One or more processors within one or more devices can identify any actual/existing or expected failure or degradation of the various components within the system. Such components may include communication devices, communication channels or links, interfaces, interconnections, etc. When an actual/existing or expected failure or degradation is identified, the affected components may be serviced or devices within the system may operate to mitigate any reduction in performance caused by such problems. Such SA functionality/capability may be implemented in one communication device or in a distributed manner across a number of devices in a communication system. | 03-19-2015 |