A receiver device includes circuitry to measure an error vector of a pulse amplitude modulation (PAM) sequence in a signal received from a transmitter and control logic coupled to the circuitry. The control logic removes estimated linear components from the measured error vector to generate a non-linear error vector. The control logic further determines, with reference to a set of lookup table (LUT) values, one or more tuning parameters for the PAM sequence based on the non-linear error vector and modifies the set of LUT values according to the one or more tuning parameters. The control logic further provides the modified set of LUT values to the transmitter, which when used by the transmitter to add digital pre-distortion to the PAM sequence, causes the non-linear error to be at least partially removed from the signal.

A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain.

Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded.

A receiver device includes circuitry to measure an error vector of a pulse amplitude modulation (PAM) sequence in a signal received from a transmitter and control logic coupled to the circuitry. The control logic removes estimated linear components from the measured error vector to generate a non-linear error vector. The control logic further determines, with reference to a set of lookup table (LUT) values, one or more tuning parameters for the PAM sequence based on the non-linear error vector and modifies the set of LUT values according to the one or more tuning parameters. The control logic further provides the modified set of LUT values to the transmitter, which when used by the transmitter to add digital pre-distortion to the PAM sequence, causes the non-linear error to be at least partially removed from the signal.

A physical layer transceiver for connecting a host device to a wireline channel medium includes a host interface for coupling to the host device, a line interface for coupling to the channel medium, a transmit path operatively coupled to the host interface and the line interface, a receive path operatively coupled to the line interface and the host interface, and adaptive filter circuitry operatively coupled to at least one of the transmit path and the receive path for filtering signals on the at least one of the transmit path and the receive path, the adaptive filter circuitry including a non-linear equalizer. The non-linear equalizer may be a neural network equalizer based on a multi-layer perceptron or a radial-basis function, or may be a linear equalizer with a non-linear activation function. The non-linear equalizer also may have a front-end filter to reduce input complexity.

An apparatus and method for transmitting digital broadcast signal are provided. The apparatus includes a group formatter to format a data group including mobile service data, where the group formatter further maps the mobile service data into a data group of interleaved format, adds N training sequences into a corresponding location of the data group of interleaved format, adds signaling data into the data group of interleaved format, inserts place holder bytes for MPEG header and non-systematic Reed-Solomon (RS) parity into the data group of interleaved format, and deinterleaves the mobile service data in the data group of interleaved format, a non-systematic RS encoder to non-systematic RS encode the mobile service data in the formatted data group and insert non-systematic RS parity obtained from the non-systematic RS encoding into the formatted data group.

A method includes, in a receiver, receiving a superposition of multiple signals originating from multiple transmitters. A symbol interval of the superposition is transformed in the receiver into a frequency domain. A start time of the symbol interval to be transformed is set in accordance with a criterion that reduces Inter-Symbol Interference (ISI) in the transformed symbol interval. At least one of the multiple signals is demodulated in the receiver using the transformed symbol interval.

An apparatus and method for transmitting digital broadcast signal are provided. The apparatus includes a group formatter to format a data group including mobile service data, where the group formatter further maps the mobile service data into a data group of interleaved format, adds N training sequences into a corresponding location of the data group of interleaved format, adds signaling data into the data group of interleaved format, inserts place holder bytes for MPEG header and non-systematic Reed-Solomon (RS) parity into the data group of interleaved format, and deinterleaves the mobile service data in the data group of interleaved format, a non-systematic RS encoder to non-systematic RS encode the mobile service data in the formatted data group and insert non-systematic RS parity obtained from the non-systematic RS encoding into the formatted data group.

A data channel on an integrated circuit device includes a non-linear equalizer having as inputs digitized samples of signals on the data channel, decoding circuitry configured to determine from outputs of the non-linear equalizer a respective value of each of the signals, and adaptation circuitry configured to adapt parameters of the non-linear equalizer based on respective ones of the value. The non-linear equalizer includes a non-linear filter portion, and a front-end filter portion configured to reduce numbers of the inputs from the digitized samples. The non-linear equalizer may be a neural network equalizer, such as a multi-layer perceptron neural network equalizer, a reduced complexity multi-layer perceptron neural network equalizer, or a radial-basis function neural network equalizer. Alternatively, the non-linear equalizer may include a linear filter and a non-linear activation function, which may be a hyperbolic tangent function.

Methods, apparatuses, and systems for improved channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system are discussed. In one example discussed herein, joint two-dimensional Minimum Mean-Square Error (2D-MMSE) channel estimation is performed on any Resource Element (REs) containing a reference signal in a Resource Block (RB), one-dimensional Minimum Mean-Square Error (1D-MMSE) channel estimation is performed in the frequency domain on each OFDM symbol in the RB, and then channel estimation is performed in the time domain on each frequency sub-carrier in the RB. In another example discussed herein, Power Delay Profiles (PDPs) and/or frequency correlations are calculated using minimax optimization and then stored in a Look-Up Table (LUT) indexed by estimated Signal to Noise Ratio (SNR) and the estimated maximum delay spread. A portable device could use such an LUT in MMSE calculations.