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: 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 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: A transmitter may map, using a selected modulation constellation, each of C? bit sequences to a respective one of C? symbols, where C? is a number greater than one. The transmitter may process the C? symbols to generate C? inter-carrier correlated virtual subcarrier values. The transmitter may decimate the C? virtual subcarrier values down to C physical subcarrier values, C being a number less than C?. The transmitter may transmit the C physical subcarrier values on C orthogonal frequency division multiplexed (OFDM) subcarriers. The modulation constellation may be an N-QAM constellation, where N is an integer. The processing may comprise filtering the C? symbols using an array of C? filter tap coefficients. The filtering may comprise cyclic filtering. The filtering may comprise multiplication by a circulant matrix populated with the C? filter tap coefficients.

Abstract: A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit.

Abstract: Method for communication channel coordination between nodes, each node including at least one of a transmitter and a receiver, for transmitting and receiving signals over residential electrical cables. The residential electrical cables include at least one active wire, one neutral wire and one ground wire, at least two of the wires forming wire pairs. The method includes the procedures of, for a given one of the receiver, examining the transmitter in each one of the nodes which communicates with the receiver, selecting one of the examined transmitters as a primary transmitter, determining an optimal receive wire pair for the receiver to receive the signals transmitted between the primary transmitter and the receiver, informing all the examined transmitters of the determined optimal receive wire pair, and tracking at least one communication characteristic over the determined optimal receive wire pair.

Abstract: Apparatus, for transmitting and receiving signals over residential electrical cables, includes a processor, at least one transmitter and at least one receiver. The transmitter and the receiver are coupled with the processor, for respectively transmitting and receiving the signals. The apparatus is coupled with an electrical cable including at least one active wire, one neutral wire and one ground wire. At least two of the wires form receive wire pairs wherein at least two of the wires form at least one transmit wire pair. The processor enables the at least one receiver to be coupled with the receive wire pairs and wherein the processor dynamically switches a coupling of the at least one receiver to another one of the plurality of receive wire pairs.

Abstract: System, for transmitting and receiving signals over residential electrical cables includes at least one active wire, one neutral wire and one ground wire. The system includes at least two power line modems, each one of the two power line modems including a processor, transmitters and at least one receiver, transmitters and the receiver being coupled with the processor, for respectively transmitting and receiving the signals. At least two of the wires form at least one receive wire pair and at least two of the wires form at least one transmit wire pair. Each one of the transmitters defines a respective carrier wave range over the transmit wire pair, the processor determining a frequency carrier wave for the signals when the signals are transmitted. A given one of the transmitters transmits the signals if the frequency carrier wave is in the carrier wave range of the given one of the transmitters.

Abstract: Method for transmitting and receiving signals over at least one channel between at least one transmitter and at least one receiver, the channel comprising at least one group of sub-channels, the group comprising at least one sub-channel, including the procedures of estimating at least one line characteristic of the channel and selecting a transmission scheme for each group of the at least one group of sub-channels according to the estimated line characteristic, wherein the transmission scheme is selected between a single spatial stream transmission scheme and a multiple spatial stream transmission scheme.

Abstract: A method for a network device of a powerline communications network includes selecting between a default preamble signal and a network-specific preamble signal specific to the network but not to a neighboring network and transmitting at least user data in conjunction with the selected preamble signal. Another method for a network device of a powerline communications network includes tuning a sensor to detect network-specific preamble signals specific to the network but not to a neighboring network and receiving at least user data associated with the preamble signals.

Abstract: A novel and useful apparatus for and method of multiple input multiple output (MIMO) detection for use in MIMO based communication systems. The mechanism of the invention performs a simplified tree search utilizing a single stage expansion of the most likely first symbol candidates, in the case of a 2×2 MIMO system. The invention also provides a refinement mechanism operative to significantly improve the soft information (i.e. log likelihood ratio) of the list of candidates. To improve the soft information, the mechanism applies one or more refinement rounds to generate additional candidates for both first and second detected symbols.

Abstract: A novel and useful apparatus for and method of multiple input multiple output (MIMO) detection for use in MIMO based communication systems. The mechanism of the invention performs a simplified tree search utilizing a single stage expansion of the most likely first symbol candidates, in the case of a 2×2 MIMO system. The invention also provides a refinement mechanism that is operative to significantly improve the soft information (i.e. log likelihood ratio) of the list of candidates. To improve the soft information, the mechanism applies one or more refinements rounds to generate additional candidates for both first and second detected symbols.

Abstract: A novel and useful apparatus for and method of multiple input multiple output (MIMO) detection for use in MIMO based communication systems. The mechanism of the invention performs a simplified tree search utilizing a single stage expansion of the most likely first symbol candidates, in the case of a 2×2 MIMO system. The invention also provides a refinement mechanism that is operative to significantly improve the log likelihood (LLR) of the list of candidates. To improve the LLR, the mechanism applies refinements rounds to generate additional candidates for both first and second detected symbols.

Abstract: A method for conveying digital data from a transmitter to a receiver includes specifying a spectral filtering profile to be applied in conveying the data. A sequence of input symbols is generated at the transmitter, corresponding to the data to be conveyed. The input symbols are precoded at the transmitter using Tomlinson-Harashima preceding responsive to the specified profile, so as to generate a corresponding sequence of precoded symbols. The precoded symbols are filtered in accordance with the specified profile. The precoded and filtered symbols are decoded at the receiver so as to recover the data therefrom.

Abstract: A method for decoding a sequence of symbols encoded by an encoding system with a plurality of possible states and transmitted over a channel, wherein the encoding system output can be represented by a trellis diagram. The method includes receiving a signal corresponding to the sequence of symbols transmitted over the channel and responsive to the signal, finding respective old state metrics for one or more of the possible states of the encoding system that correspond to a given symbol in the sequence. Respective transition metrics are determined for state transitions that link the one or more possible states for which the old state metrics were found to at least some of the possible states of the encoding system that correspond to a succeeding one of the symbols in the sequence.

Abstract: A digital data receiver, for receiving a signal that is transmitted over a channel having a channel response and is filtered with a predetermined filter response. The receiver includes a decision device, coupled to receive a sequence of equalized samples and to generate, responsive thereto, a corresponding sequence of estimated symbols. A feed-forward equalizer receives a sequence of input samples of the signal and generates responsive to the input samples, forward-equalized samples. A decision feedback equalizer (DFE), which receives the sequence of estimated symbols, includes an adaptive element, which processes the estimated symbols responsive to the channel response, and a fixed element, which processes the estimated symbols responsive to the predetermined filter response. The DFE generates feedback-equalized samples by combined operation of the adaptive and fixed elements.

Abstract: Impulsive noise is detected for each discrete multi-tone (DMT) symbol. If impulsive noise is detected, all bytes, which belong to the associated DMT symbol are tagged by “erasure bits”. After interleaving, Reed-Solomon decoding is initially performed without erasures. If the decoding fails, it is performed again, this time with erasures. Reed-Solomon decoders report failure with relatively high certainty, and thus, if the first stage (decoding without erasures) includes failure or errors due to impulsive noise, the second stage of decoding is performed again with erasures.

Abstract: A method for transmitting a succession of input data samples over a channel having a given channel response includes generating a set of candidate signal point sequences responsive to the input data samples, such that the input data samples are recoverable from a final signal derived from the candidate sequences. The succession of input data samples is mapped into a succession of interim signal point sequences, selected from among the candidate signal point sequences according to a signal shaping criterion. The interim signal point sequences are precoded according to the given channel response and further according to a whitening transformation. The precoded sequences are filtered in accordance with the whitening transformation, thus generating the final signal to be transmitted over the channel to a receiver.

Abstract: A method is described for mapping digital input data, including a sequence of input samples, into an interim signal point sequence, for use in conjunction with a single carrier modulation transmitter. The method includes generating a set of candidate signal point sequences, for each input sample, selecting an interim signal point sequence, into which to map the sequence of input samples, from among the set of candidate signal point sequences, so as to obtain a low peak power value of a final signal generated from the interim signal point sequence, and using a single carrier modulation transmitter to transmit the final signal to a receiver.

Abstract: A high-speed transmitter, which generates an output signal stream having a specified spectral profile. The transmitter includes a Tomlinson-Harashima precoder, which is adapted to receive a sequence of input symbols having a given input constellation and to generate, responsive to the specified spectral profile, a corresponding sequence of precoded symbols. A transmit digital filter is adapted to apply a transmit filter response, in accordance with the specified spectral profile, to the precoded symbols so as to generate a corresponding sequence of output symbols, having a given output constellation, to be transmitted in the output stream.