Abstract: A single hardware device (“unified NDR core”) that supports a narrowband digital return (NDR) channel for a plurality of remote PHY devices. The unified NDR core may be located within a cable headend. The unified NDR core comprises a single digital-to-analog converter (DAC) which converts digital payloads carried by digital packets received from the plurality of Remote PHY devices into a RF signal. The unified NDR core further comprises a transmitter for sending the RF signal to an Out-of-Band (OOB) Termination System. The unified NDR core supports a plurality of narrowband digital return (NDR) channels for the plurality of remote PHY devices.

Abstract: Assigning an appropriate modulation profile for an orthogonal frequency-division multiplexing (OFDM) channel. The current modulation profile assigned to a specific OFDM modem for communicating over a specific OFDM channel is examined to determine whether to consider reassigning the specific OFDM modem to a different modulation profile. Only upon determining consideration should be given, an assessment is made as to which modulation profile, of a set of candidate modulation profiles available to that OFDM modem for communicating over the specific OFDM channel, should be assigned to the specific OFDM modem using linear domain averaging over the OFDM subcarriers of the ratios between a Mean Error Rate (MER) threshold per subcarrier for the specific OFDM modem and the MER reported by the specific OFDM modem per subcarrier. A new modulation profile is assigned to the specific modem based on the assessment.

Abstract: Assigning an appropriate modulation profile for an orthogonal frequency-division multiplexing (OFDM) channel. The current modulation profile assigned to a specific OFDM modem for communicating over a specific OFDM channel is examined to determine whether to consider reassigning the specific OFDM modem to a different modulation profile. Only upon determining consideration should be given, an assessment is made as to which modulation profile, of a set of candidate modulation profiles available to that OFDM modem for communicating over the specific OFDM channel, should be assigned to the specific OFDM modem using linear domain averaging over the OFDM subcarriers of the ratios between a Mean Error Rate (MER) threshold per subcarrier for the specific OFDM modem and the MER reported by the specific OFDM modem per subcarrier. A new modulation profile is assigned to the specific modem based on the assessment.

Abstract: Assigning an appropriate modulation profile for an orthogonal frequency-division multiplexing (OFDM) channel. The current modulation profile assigned to a specific cable modem for communicating over a specific OFDM channel is examined to determine whether to consider reassigning the specific cable modem to a different modulation profile. Only upon determining consideration should be given, an assessment is made as to which modulation profile, of a set of candidate modulation profiles available to that cable modem for communicating over the specific OFDM channel, should be assigned to the specific cable modem using linear domain averaging over the OFDM subcarriers of the ratios between a Mean Error Rate (MER) threshold per subcarrier for the specific cable modem and the MER reported by the specific cable modem per subcarrier. A new modulation profile is assigned to the specific modem based on the assessment.

Abstract: Assigning an appropriate modulation profile for an orthogonal frequency-division multiplexing (OFDM) channel. The current modulation profile assigned to a specific cable modem for communicating over a specific OFDM channel is examined to determine whether to consider reassigning the specific cable modem to a different modulation profile. Only upon determining consideration should be given, an assessment is made as to which modulation profile, of a set of candidate modulation profiles available to that cable modem for communicating over the specific OFDM channel, should be assigned to the specific cable modem using linear domain averaging over the OFDM subcarriers of the ratios between a Mean Error Rate (MER) threshold per subcarrier for the specific cable modem and the MER reported by the specific cable modem per subcarrier. A new modulation profile is assigned to the specific modem based on the assessment.

Abstract: A distribution system that may include multiple radio frequency outputs, a group of channel processing and digital up conversion units, and a set of digital to analog converters. The set of digital to analog converters is coupled between the group of channel processing and digital up conversion units and the multiple radio frequency outputs. The group of channel processing units may be arranged to generate multiple digital multiplexes and to provide the multiple digital multiplexes to the set of digital to analog converters. Each digital multiplex comprises digital broadcast channels provided from at least two channel processing and digital up conversion units. The set of the digital to analog converters may be arranged to convert the multiple digital multiplexes to provide multiple analog multiplexes and to provide the multiple analog multiplexes to the multiple radio frequency outputs.

Abstract: A distribution system that may include multiple radio frequency outputs, a group of channel processing and digital up conversion units, and a set of digital to analog converters. The set of digital to analog converters is coupled between the group of channel processing and digital up conversion units and the multiple radio frequency outputs. The group of channel processing units may be arranged to generate multiple digital multiplexes and to provide the multiple digital multiplexes to the set of digital to analog converters. Each digital multiplex comprises digital broadcast channels provided from at least two channel processing and digital up conversion units. The set of the digital to analog converters may be arranged to convert the multiple digital multiplexes to provide multiple analog multiplexes and to provide the multiple analog multiplexes to the multiple radio frequency outputs.

Abstract: A device that may include a router and may also include narrowband generators arranged to generate samples of narrowband channels, a digital up converter (DUC). The DUC may include multiple DUC inputs. Different DUC inputs are associated with different frequency ranges. The router may include multiple router inputs, multiple router outputs and a routing circuit. The multiple router outputs are coupled to the multiple DUC inputs. The multiple router inputs are coupled to the narrowband generators. The routing circuit may include a re-sequencing memory module that is arranged to receive the samples of narrowband channels from the narrowband generator according to an input order and to output the samples of the narrowband channels to the multiple router outputs according to an output order that is responsive to an allocation of frequencies to the samples of the narrowband channels.

Abstract: A device that may include a router and may also include narrowband generators arranged to generate samples of narrowband channels, a digital up converter (DUC). The DUC may include multiple DUC inputs. Different DUC inputs are associated with different frequency ranges. The router may include multiple router inputs, multiple router outputs and a routing circuit. The multiple router outputs are coupled to the multiple DUC inputs. The multiple router inputs are coupled to the narrowband generators. The routing circuit may include a re-sequencing memory module that is arranged to receive the samples of narrowband channels from the narrowband generator according to an input order and to output the samples of the narrowband channels to the multiple router outputs according to an output order that is responsive to an allocation of frequencies to the samples of the narrowband channels.

Abstract: A method that includes providing to multiple inverse fast Fourier transform (IFFT) and polyphase circuits multiple baseband channels so that different IFFT and polyphase circuits receive different sets of baseband channels; applying IFFT operations and the polyphase filtering operations by the multiple IFFT and polyphase circuits to provide multiple converted channels; wherein different IFFT and polyphase circuits output different sets of converted channels that at least partially populate different IFFT grids that comprise different frequency bins; wherein frequency bins of a same IFFT grid of the different IFFT grids are spaced apart from each other by a first spacing; frequency shifting one or more sets of the converted channels to provide an output set of sub-channels; wherein the output set of sub-channels at least partially populates an output frequency grid in which output sub-channels originating from different sets of converted channels are of interleaving frequencies and in which the spacing between

Abstract: A method that includes providing to multiple inverse fast Fourier transform (IFFT) and polyphase circuits multiple baseband channels so that different IFFT and polyphase circuits receive different sets of baseband channels; applying IFFT operations and the polyphase filtering operations by the multiple IFFT and polyphase circuits to provide multiple converted channels; wherein different IFFT and polyphase circuits output different sets of converted channels that at least partially populate different IFFT grids that comprise different frequency bins; wherein frequency bins of a same IFFT grid of the different IFFT grids are spaced apart from each other by a first spacing; frequency shifting one or more sets of the converted channels to provide an output set of sub-channels; wherein the output set of sub-channels at least partially populates an output frequency grid in which output sub-channels originating from different sets of converted channels are of interleaving frequencies and in which the spacing between

Abstract: A convolutionally encoded frame to be decoded includes a first portion of bits having additional error protection and another portion without additional error protection. The decoding of the frame involves reverse Viterbi decoding or Viterbi decoding on a reversed bit sequence followed by applying a serial list Viterbi algorithm to the first portion. The result is that the list of probable sequences have unique sets of bits in the first portion.

Abstract: A convolutionally encoded frame to be decoded includes a first portion of bits having additional error protection and another portion without additional error protection. The decoding of the frame involves reverse Viterbi decoding or Viterbi decoding on a reversed bit sequence followed by applying a serial list Viterbi algorithm to the first portion. The result is that the list of probable sequences have unique sets of bits in the first portion.

Abstract: An apparatus for and method of generating normalized soft decision information output from an inner decoder (i.e. equalizer) in a communications receiver. The invention is operative to normalize the soft decision information before it enters a soft outer decoder. The normalization is performed using a noise power estimate that is dynamically calculated in response to changing noise statistics on the channel. The normalized soft decision output is then applied to the soft outer decoder thus realizing maximum performance therefrom. The noise power estimate is derived from the training sequence and/or the data portion of the received signal. Both types of estimates are calculated. A binary or smoothly weighted average is calculated using both types of estimates. The weighting factor is determined based on one or more performance metrics, such as the Signal to Noise Ratio (SNR).

Abstract: A novel and useful whitening matched filter (WMF) for use in a communications receiver. The WMF is constructed by cascading a matched filter and a noise-whitening filter. The response of the matched filter is derived from the time reversed complex conjugate of the channel impulse response. The whitening filter is derived by extracting the minimum phase portion of the mixed phase channel impulse response using homomorphic deconvolution. The whitening filter is implemented using either an FIR or IIR filter adapted to process the data received before and after the training sequence using a minimum phase system in a direction in time opposite to that of the direction of corresponding data sample processing performed by the equalizer.

Abstract: A novel and useful apparatus for and method of interference reduction in a communications receiver. The invention first finds the channel estimate and the noise vector from the receive signal. An interference detector is then used to choose an appropriate compensation filter and select between adaptive and deterministic moving average models for noise prediction. After compensation filtering, a new channel estimate and noise vector is calculated. The new noise vector is used to determine noise whitening coefficients if the adaptive model is used. In the deterministic model case, the coefficients do not need to be calculated since they are already known, having been calculated a priori. The noise whitening coefficients are then used in an equalizer such as a Viterbi algorithm based equalizer.