Abstract: A system and method are provided for implementing a soft Reed-Solomon (RS) decoding scheme, technique or algorithm to improve physical layer performance in cable modems and cable gateways. At 1024-QAM, a receiver is provided in which a signal to noise ratio is reduced by at least about 1 dB relaxing design considerations and specifications for other components in the system including for the tuner. A soft-RS-symbol generation scheme is provided to enable soft-input RC decoding in a forward error correction (FEC) module connected to a QAM demodulator. The RS decoding scheme is implemented without significantly complicating hardware or processing overhead. A typical receiver hardware requirement in an FEC module to implement the disclosed scheme may be comparatively modest, e.g., on an order of approximately 50K gates.

Abstract: A system and method are provided for implementing a peak-to-average power ratio (PAPR) reduction scheme for Orthogonal Frequency-Division Multiple Access (OFDMA) modulation. A unique PAPR reduction scheme for OFDMA modulation for systems operated according to a DOCSIS standard achieves results similar to those attributable to tone reservation schemes in a manner that does not negatively affect an amount of available data capacity, particularly in implementations with limited numbers of subcarriers. The disclosed systems and methods are particularly adaptable to next generation cable gateways and/or next generation cable modems. These next generation cable gateways and/or cable modems may find particular utility in advanced hybrid fiber/coaxial cable systems. The adaptable cable gateways/modems may include a cable gateway system-on-chip (SOC) configuration. The disclosed schemes may be applicable to OFDM modulation. For OFDM, however, the known tone reservation algorithms also may be employed.

Abstract: An apparatus may include a processor circuit, and a dynamic filter adjustment component for execution on the processor. The dynamic filter adjustment component may identify in a wideband communications signal a set of one or more interferer frequencies for one or more respective interferer channels of a set of communications channels to be filtered, select a kernel filter comprising a low pass filter having a channel width corresponding to a channel of the one or more interferer channels, and generate a co-channel interference (CCI) filter to stop the one or more interferer channels by inverting the kernel filter. Other embodiments are described and claimed.

Abstract: An approach is provided to mitigate phase noise by correcting common phase error and inter-carrier-interference in a received signal. The approach involves determining a received signal includes phase noise comprising at least a common phase error component and an inter-carrier-interference component. The approach also involves causing the common phase error to be corrected based on one or more pilot carriers. The approach further involves causing an estimate of a main signal component to be subtracted from the one or more pilot carriers. The approach additionally involves determining a sequence of estimated coefficients of a multiplicative phase noise sequence. The approach also involves causing the inter-carrier-inference to be corrected by processing the multiplicative phase noise sequence using the sequence of estimated coefficients. The approach further involves causing an equalized data signal to be output based on the corrected common phase error and the corrected inter-carrier-interference.

Abstract: Methods and systems to mitigate impulse interference in an OFDM QAM signal. A per-symbol noise measure, or quality measure (QM) is computed for a symbol k as a MSE of distances between carriers in the symbol and points of corresponding QAM constellations. MSE(k) is averaged over multiple symbols to compute a background signal QM, AVG_MSE(k). If MSE(k) exceeds AVG_MSE(k) by a moderate amount, symbol k may be moderately affected by impulse interference, and per-carrier SNR estimates are downgraded for all data carriers in symbol k, prior to LLR computation. SNR downgrading may be linear or step-wise based on an extent to which MSE(k) exceeds AVG_MSE(k). If MSE(k) exceeds AVG_MSE(k) by a significant amount, symbol k may be significantly affected by impulse interference, and LLRs may be set to indicate that all data carriers are erased in symbol k.

Abstract: In an Orthogonal Frequency Division Multiplex (“OFDM”) system, the problem of an interferer reducing the signal-to-noise ratio of a signal can be mitigated by generating an interferer-correction signal and subtracting it from the signal to be processed. The amplitude, frequency and phase of the interferences are determined first. The frequency is estimated by averaging the squared-magnitude of multiple FFTs of the incoming signal and then locating the spectral peaks. The phase and amplitude may be estimated from this FFT outputs or through a process of correlation in the time domain. The interferer-correction signal is generated from the estimated amplitude, frequency, and phase. The correction to be subtracted from the main signal in order to reduce the effect of the interference may be generated in the time or frequency domain. The subtraction of the correction may also be implemented in the time or frequency domains.

Abstract: An embodiment of the present invention provides a method for digital television demodulation, comprising using adjacent-channel power dependent automatic gain control (AGC) for the digital television demodulation, wherein an AGC technique takes into account a total power as well as power of adjacent channels to control gain of a gain control amplifier.

Abstract: Apparatuses, systems, and methods are directed to maintaining optimal carrier tracking performance in view of operating conditions that prevail. Such configurations employ a phase lock loop that configured to generate an estimated phase error value, a variance module configured to calculate a phase noise variance based on the estimated phase error value, and a loop control bandwidth module that calculates a loop bandwidth value based on a detected lower phase noise variance, generates modified loop filter values in accordance with the calculated loop bandwidth value, and updates the phase lock loop with the modified loop filter values. During subsequent iterations, the modified loop filter values are incrementally adjusted along a particular direction until the phase noise variance increases at which point the modified loop filter values are incrementally adjusted in an opposite direction to converge on an optimal loop bandwidth value.

Abstract: According to various embodiments, apparatus and methods disclosed herein include computing phase error of a received signal based on an estimate of a first component (e.g., in-phase component) of a transmitted signal and an analytic representation of the estimate of the first component of the transmitted signal. The analytic representation of the estimate of the first component of the transmitted signal may represent an estimate of a second component (e.g., quadrature phase component) of the transmitted signal. The analytic representation of the estimated first component may be computed using at least one of a Hilbert transform or Fourier transform on the estimated first component of the transmitted signal.

Abstract: An embodiment of the present invention provides a method for digital television demodulation, comprising using adjacent-channel power dependent automatic gain control (AGC) for the digital television demodulation, wherein an AGC technique takes into account a total power as well as power of adjacent channels to control gain of a gain control amplifier.

Abstract: Apparatus and methods are described to perform inter carrier interference (ICI) reduction or cancellation in an orthogonal frequency domain multiplexing (OFDM) receiver. A first and a second stage of ICI cancellation may be performed before inputting an estimated transmitted data carrier for forward error correction. Forward error correction may include a signal re-correction and reconstruction of the estimated transmitted data carrier prior to a further stage of ICI cancellation.

Abstract: Embodiments of methods for receiving and processing multi-band signals in wideband and narrowband environments are described herein. Other embodiments may be described and claimed.

Abstract: According to various embodiments, a method is disclosed that includes a method is disclosed that includes determining, by a receiver, a frequency offset in a signal comprising a set of orthogonal frequency division multiplexed (OFDM) symbols by determining a first difference in phase angles between a nth OFDM symbol and a nth+1 OFDM symbol on a common OFDM carrier and a first difference in phase angles between the nth+1 OFDM symbol and a nth+2 OFDM symbol on the common OFDM carrier and determining a second difference in phase angles between the first difference in phase angles between the nth OFDM symbol and the nth+1 OFDM system and the first difference in phase angles between the nth+1 OFDM symbol and the nth+2 OFDM symbol to identify the frequency offset, wherein n?{1, . . . , N}; and correcting, by the receiver, the signal using the determined frequency offset.

Abstract: Methods and systems to compute likelihood measures of demodulated, complex-coordinate data points, to and dynamically scale the likelihood measures as a function of a channel statistic, and to decode the data points from the scaled likelihood measures. Likelihood measures may be computed relative to all points, or a subset of points of a reference constellation, such as a subset of one or more nearest constellation points. Likelihood measures may be scaled as a function of a channel frequency response variance amongst a plurality of carriers, such as carriers of an OFDM signal, and/or as a function of a channel impulse response variance.

Abstract: According to various embodiments, apparatus and methods disclosed herein include computing phase error of a received signal based on an estimate of a first component (e.g., in-phase component) of a transmitted signal and an analytic representation of the estimate of the first component of the transmitted signal. The analytic representation of the estimate of the first component of the transmitted signal may represent an estimate of a second component (e.g., quadrature phase component) of the transmitted signal. The analytic representation of the estimated first component may be computed using at least one of a Hilbert transform or Fourier transform on the estimated first component of the transmitted signal.

Abstract: According to various embodiments, apparatus and methods disclosed herein may be implemented in a digital communication (wired or wireless) receiver, and relate to minimizing noise in an estimated channel frequency response at the receiver for the purposes of channel equalization. The disclosed apparatus and methods may include determining a channel impulse response based on an estimated channel frequency response. The estimated channel frequency response, the channel impulse response, or both may include noise. An impulse response mask may be determined based on the channel impulse response, and further applied to the channel impulse response to obtain a noise-reduced channel impulse response, which may be Fourier transformed to obtain a noise-reduced channel frequency response.

Abstract: Methods and systems to resolve cyclic ambiguity of a scattered-pilot based channel impulse response as a function of transmission parameter signalling (TPS), such as in a single frequency network, including to zero-pad a first orientation of the channel impulse response to an interval of an effective symbol duration of the multi-carrier signal, compute a channel frequency response from the zero-padded first orientation of the channel impulse response, and correlate components of the channel frequency response corresponding to frequencies of TPS carriers with raw channel frequency response data of obtained from the TPS carriers. Frequency response components of multiple zero-padded orientations of the channel impulse response may be correlated with the raw TPS carrier data to identify an optimum orientation of the channel impulse response. Frequency response components of subsequent zero-padded orientations may be iteratively computed from components of preceding orientations.

Abstract: A method and system for OFDM symbol timing recovery is described. A symbol timing recovery module of an OFDM receiver is configured to determine an optimum trigger point for performing a discrete Fourier transform in a manner that minimizes inter-symbol interference.

Abstract: Methods and systems to identify a codeword associated with samples of a signal from spectral content of the samples, and to estimate a frequency offset from the spectral contents. The samples may correspond to a physical layer header of a data frame. Modulation may be removed from the samples in accordance with each of a plurality of modulation sequences, each sequence associated with a corresponding codeword. Power levels in spectral contents of the modulation-removed samples are examined to identify a peak power level indicative of a match between a modulation sequence and the samples. The corresponding codeword is identified as being associated with the header, and transmission parameters associated with the identified codeword are used to decode a corresponding frame. An estimated frequency offset may be determined from a frequency associated with the peak power level.

Abstract: According to various embodiments, devices and methods disclosed herein include performing, using a processor, a linear operation on a first plurality of channel frequency responses and a plurality of corresponding predictor coefficients to estimate a new channel frequency response. Each of the plurality of corresponding predictor coefficients may be updated based on an error value and a second plurality of channel frequency responses to obtain an updated predictor coefficient. The error value may be computed based on an estimated current channel frequency response and a predicted current channel frequency response. The new channel frequency response may be used to equalize a received modulated signal including a single-carrier modulated signal, e.g., a signal modulated using a vestigial sideband modulation scheme, or a quadrature amplitude modulation scheme.