Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An outer encoder encodes input data signal to generate a first encoded signal. An inner encoder encodes a subset of the input data to generate a second encoded signal, wherein the inner encoder has a different forward error correction (FEC) than the outer encoder. A symbol mapper processes the first encoded signal and the second encoded signal to generate a sequence of discrete-valued modulation symbols.

Abstract: A demodulator processes a continuous-time signal to generate at a plurality of encoded bits. An inner decoder processes a first subset of bits within the plurality of encoded bits to correct selected ones of the first subset of bits to form a corrected first subset of bits and to generate partially corrected data from the plurality of encoded bits based on the corrected first subset of bits. An outer decoder processes the partially decoded data, to correct selected ones of a second subset of the plurality of encoded bits to form a corrected second subset of bits. A bit combiner generates data estimates by combining the corrected first subset of bits and the corrected second subset of bits.

Abstract: 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.

Abstract: 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.).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.