Abstract: A receiver may be operable to receive a signal. A sequence estimation module of the receiver may generate estimated symbols corresponding to the received signal. The generating of the estimated symbols may use tap information associated with one or both of a pulse shaper via which the signal was transmitted and an input filter of the receiver. The sequence estimation module may generate a reconstructed signal based on the estimated symbols and the tap information. A feed forward equalizer (FFE) of the receiver may adapt a plurality of tap coefficients of the FFE based on the reconstructed signal. The signal may be equalized via the FFE. The adaptation of the tap coefficients of the FFE may be based on a least-mean-square (LMS) process for minimizing a mean square of the error signal. An output signal of the FFE may comprise a power gain compensation.

Abstract: A method and system for optimizing symbol mapping in partial response based communications that are based on use of pulse-shaping that incorporates a predetermined amount of inter-symbol interference (ISI). Optimizing symbol mapping symbol mapping may comprise configuring optimized constellation mapping for use in mapping and/or de-mapping data communicated using the partial response pulse-shaping. In this regard, the optimized constellation mapping may be based on a reference constellation mapping that is utilized for reference modulation scheme, and the configuring comprises applying adjustments to one or more constellation points in the reference constellation mapping. The optimized constellation mapping may be configured to optimize an applicable minimum distance for one or more selected error patterns for a given spectral compression applied during partial response based communications.

Abstract: A receiver may be operable to receive a QAM-based, inter-symbol correlated (ISC) signal having pilot overhead of 5% at a signal-to-noise ratio (SNR). The receiver may be operable to process the QAM-based, ISC signal to output information at a particular rate with a symbol error rate lower than or equal to 1e-2. The first SNR may be at least 3 dB below a SNR required to achieve the same particular information rate and the same symbol error rate while processing a signal having zero inter-symbol interference.

Abstract: An electronic receiver comprises a nonlinear distortion modeling circuit and a nonlinear distortion compensation circuit. The nonlinear distortion modeling circuit is operable to determine a plurality of sets of nonlinear distortion model parameter values, where each of the sets of nonlinear distortion model parameter values representing nonlinear distortion experienced by signals received by the electronic receiver from a respective one a plurality of communication partners. The nonlinear distortion compensation circuit is operable to use the sets of nonlinear distortion model parameter values for processing of signals from the plurality of communication partners. Each of the sets of nonlinear distortion model parameter values may comprises a plurality of values corresponding to a plurality of signal powers. The sets of nonlinear distortion model parameters may be stored in a lookup table indexed by a signal strength parameter.

Abstract: A receiver may be dynamically configurable, during run-time, into a plurality of modes of operation. In a first mode of operation the receiver may demodulate received signals having relative low inter-symbol correlation using a near zero ISI filter and symbol slicing. In a second mode of operation the receiver may demodulate received signals having relatively high inter-symbol correlation using an input filter configured to achieve a desired total partial response and a sequence estimation algorithm.

Abstract: Circuitry for use in a receiver may comprise: a front-end circuit operable to receive an orthogonal frequency division multiplexing (OFDM) symbol on a first number of physical subcarriers. The circuitry may comprise a decoding circuit operable to decode the OFDM symbol using an inter-carrier interference (ICI) model, the decoding resulting in a determination of a sequence of symbols, comprising a second number of symbols, that most-likely correspond to the received OFDM symbol, where the second number is greater than the first number. The sequence of symbols may comprise N-QAM symbols, N being an integer. The ISCI model may be based, at least in part, on non-linearity experienced by the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver. The ISCI model may be based, at least in part, on phase-noise introduced to the OFDM symbol during transmission by a transmitter, propagation over a channel, and/or reception by the receiver.

Abstract: A receiver comprises a sequence estimation circuit and a soft-input-soft-output (SISO) decoder. The sequence estimation circuit comprises circuitry operable to generate first soft bit decisions for symbols of a received inter-symbol-correlated signal. The SISO decoder comprises circuitry operable to decode the first soft bit decisions to generate corrected soft bit decisions. The circuitry of the sequence estimation circuit is operable to generate, based on the corrected soft bit decisions, second soft bit decisions for the symbols of the received inter-symbol-correlated signal, which are improved/refined relative to the first soft bit decisions.

Abstract: Methods and systems are provided for coarse phase estimation for highly-spectrally efficient communications. An example method may include, equalizing, in a receiver, a received inter-symbol correlated (ISC) signal to generate an equalized ISC signal. A phase adjustment signal may be generated based on an ISC feedback signal. The ISC feedback signal may be generated using a sequence estimation process and a non-linearity model. A phase of the equalized ISC signal may be adjusted using the generated phase adjustment signal, to generate a phase adjusted partial response signal. The phase adjustment signal may be generated based on a phase difference between the equalized ISC signal and the partial response feedback signal.

Abstract: Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, mapping, in a transmitter, a plurality of transmit bits to a plurality of symbols at a symbol rate that is based on an oscillator signal. The plurality of symbols may be processed via a filter. The processing may result in an inter-symbol correlated (ISC) signal. The oscillator signal may be frequency divided to generate one or more pilot signals having a frequency that is a sub-harmonic of a frequency of the oscillator signal. The pilot signal may be injected into the ISC signal. The injecting may result in an ISC signal with timing carrier. The ISC signal with timing carrier may be transmitted. Gain of the one or more pilot signals may be adjusted based on a spectral mask value associated with the transmitting.

Abstract: A sequence estimation circuit of a receiver may receive a sample of an inter-symbol correlated (ISC) signal corresponding to a time instant when phase and/or amplitude of the ISC signal is a result of correlation among a plurality of symbols of a transmitted symbol sequence. The sequence estimation circuit may calculate a residual signal value based on the sample of the ISC signal and based on a survivor sequence. The sequence estimation circuit may generate one or more branch vector hypotheses based on the residual signal value, where each of the hypotheses comprises a plurality of symbols. The sequence estimation circuit may generate an estimate of one or more of the plurality of transmitted symbols based on the one or more branch vector hypotheses.

Abstract: A receiver may comprise a sequence estimation circuit and operate in at least two modes. In a first mode, the sequence estimation circuit may process OFDM symbols received on a first number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is greater than the first number. In a second mode, the sequence estimation circuit may process OFDM symbols received on a second number of data-carrying subcarriers to recover a number of mapped symbols per OFDM symbol that is equal to the second number. The second number may be equal to or different from the first number. While the receiver operates in the first mode, the sequence estimation circuit may be operable to generate candidate vectors and process the candidate vectors using a controlled ISCI model to generate reconstructed physical subcarrier values.

Abstract: Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, filtering, in a receiver, a received inter-symbol correlated (ISC) signal to generate a filtered ISC signal. The method may further include locking to a timing pilot signal of the filtered ISC signal. The timing pilot signal may include a sub-harmonic frequency of a clock signal associated with the received ISC signal. A timing pilot estimate signal of the timing pilot signal may be generated. The timing pilot estimate signal may be cancelled from the filtered partial response signal to generate an output ISC signal. The timing pilot signal includes a signal at ±(1/n*Fbaud), where n is an integer greater than 2, and Fbaud is a symbol rate of the clock signal. The clock signal may be recovered from the filtered ISC signal.

Abstract: A transmitter inserts parity samples into a stream of information symbols in an inter-symbol correlated (ISC) signal. The inserted parity samples may be utilized to generate estimates of corresponding information symbols when they are received by a receiver. The information symbols may be pulse shaped by a first pulse shaping filter characterized by a first response. The parity samples may be pulsed shaped by a second pulse shaping filter characterized by a second response. The first response and the second response are diverse or uncorrelated. The transmitter may transmit the ISC signal comprising the pulse shaped information symbols and the pulse shaped parity samples. The parity samples may be generated utilizing a non-linear function over a plurality of the information symbols. The non-linear function may be diverse from a partial response signal convolution corresponding to the information symbols and is designed according to a desired SNR value at the receiver.

Abstract: A method and system for dynamic configuring of one or both of a transmitter pulse-shaping filter and a receiver pulse-shaping filter to generate a total partial response that incorporates a predetermined amount of inter-symbol interference (ISI). The predetermined amount of ISI is determined based on an estimation process during extraction of data from an output of the receiver pulse-shaping filter, such that performance of total partial-response-based communication matches or surpasses performance of communication incorporating filtering based on no or near-zero ISI. The reconfiguring may comprise obtaining data relating to changes affecting one or more of: the pulse-shaping filtering, and a channel and/or an interface used in the communication of data based on the total partial response, and adjusting the filter configuration, such as by determining a new optimized filtering configuration or changes to existing configurations (e.g., by applying a filtering optimization process).

Abstract: A method and system for a sequence estimation in a receiver, such as for use when receiving a sample of a received inter-symbol correlated (ISC) signal corresponding to a transmitted vector of L symbols, with L being a integer greater than 1, and with symbol L being a most-recent symbol and symbol 1 being least recent symbol of the vector. A plurality of candidate vectors may be generated, wherein element L?m of each candidate vector holding one of a plurality of possible values of the symbol L?m, with m is an integer greater than or equal to 1, and elements L?m+1 through L of each candidate vectors holding determined filler values. A plurality of metrics may be generated based on the plurality of candidate vectors, and based on the generated plurality of metrics, a best one of the possible values of the symbol L?m may be selected.

Abstract: A receiver may receive a signal that was generated by passage of symbols through a non-linear circuit. An equalizer of the receiver may equalize the received signal based on a first non-linearity compensated, inter-symbol correlated (ISC) feedback signal to generate an equalized signal. The receiver may correct a phase error of the equalized signal to generate a phase-corrected equalized signal. The phase correction may be based on a second, non-linearity compensated, inter-symbol correlated (ISC) feedback signal.

Abstract: A receiver receives an inter-symbol correlated (ISC) signal with information symbols and a corresponding parity symbol. Values of information symbols are estimated utilizing parity samples that are generated from the parity symbols. One or more maximum likelihood (ML) decoding metrics are generated for the information symbols. One or more estimations are generated for the information symbols based on the one or more ML decoding metrics. A parity metric is generated for each of the one or more generated estimations of the information symbols. The parity metric is generated by summing a plurality of values of one of the generated estimations to generate a sum, and wrapping the sum to obtain a parity check value that is within the boundaries of a symbol constellation utilized in generating the information symbols.

Abstract: A receiver may be operable to receive an inter-symbol correlated (ISC) signal, and generate a plurality of soft decisions as to information carried in the ISC signal. The soft decisions may be generated using a reduced-state sequence estimation (RSSE) process. The RSSE process may be such that the number of symbol survivors retained after each iteration of the RSSE process is less than the maximum likelihood state space. The plurality of soft decisions may comprise a plurality of log likelihood ratios (LLRs). Each of the plurality of LLRs may correspond to a respective one of a plurality of subwords of a forward error correction (FEC) codeword.

Abstract: A method and system for configuring one or both of a transmitter pulse-shaping filter and a receiver pulse-shaping filter to generate a total partial response that incorporates a predetermined amount of inter-symbol interference (ISI), based on one or more defined performance-related variables and one or more set constraints that are applicable to one or both of the transmitter pulse-shaping filter and the receiver pulse-shaping filters. The predetermined amount of ISI is determined based on an estimation process during extraction of data from an output of the receiver pulse-shaping filter, such that performance of total partial response based communication matches or surpasses performance of communication incorporating filtering based on no or near-zero ISI. The configuring may comprise determining optimized filtering configuration, by applying an optimization process which is based on, at least in part, the one or more constraints and the one or more performance-related variables.

Abstract: One or more embodiments describe a decision feedback equalizer for highly spectrally efficient communications. A method may be performed in a decision feedback equalizer (DFE). The method may include initializing values of tap coefficients of the DFE based on values of tap coefficients of a partial response filter through which said transmitted symbols passed en route to said sequence estimation circuit. The method may include receiving estimates of transmitted symbols from a sequence estimation circuit, and receiving an error signal that is generated based on an estimated partial response signal output by the sequence estimation circuit. The method may include updating values of tap coefficients of the DFE based on the error signal and the estimates of transmitted symbols. The method may include generating one or more constraints that restrict the impact of the error signal on the updating of the values of the tap coefficients of the DFE.