Apparatus and methods for combined precoding and shaping generating an uncorrelated sequence of samples

A method for transmitting data, including a succession of input data samples, over a channel having a given channel response, the method comprising:

• 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;
• mapping the succession of input data samples into a succession of interim signal point sequences, selected from among the candidate signal point sequences according to a signal shaping criterion;
• preceding the interim signal point sequences according to the given channel response and further according to a whitening transformation;
• and
• filtering the precoded sequences in accordance with the whitening transformation, thus generating the final signal to be transmitted over the channel to a receiver,
• wherein preceding the interim signal point sequences comprises initiating the precoding responsive only to the given channel response and then adapting the preceding responsive to the whitening transformation.

Signal processing apparatus for use in a transmitter, which processes data, including a succession of input data samples, for transmission over a channel having a given channel response, the apparatus comprising:

• a candidate set generator, which generates 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;
• an interim signal point sequence selector, which maps the succession of input data samples into a succession of interim signal point sequences, which are selected from among the candidate signal point sequences according to a signal shaping criterion;
• a precoder, which precodes the interim signal point sequences according to the given channel response and further according to a whitening transformation;
• and
• a whitening filter, which filters the precoded sequences in accordance with the whitening transformation, thus generating the final signal.

Signal processing apparatus for use in a transmitter, which processes data, including a succession of input data samples, for transmission over a channel having a given channel response, the apparatus comprising:

• a candidate set generator, which generates 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;
• an interim signal point sequence selector, which maps the succession of input data samples into a succession of interim signal point sequences, which are selected from among the candidate signal point sequences according to a signal shaping criterion;
• a precoder, which precodes the interim signal point sequences according to the given channel response and further according to a whitening transformation, wherein the precoder initiates the preceding responsive only to the given channel response and then adapts the preceding responsive to the whitening transformation;
• and
• a whitening filter, which filters the precoded sequences in accordance with the whitening transformation, thus generating the final signal.