Metric calculation design for variable code rate decoding of broadband trellis, TCM, or TTCM

A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:

• a square output multiplexor that selectively outputs a plurality of in-phase (I) associated outputs and a plurality of quadrature (Q) associated outputs according to the rate control sequence;
• wherein the rate control sequence comprises a plurality of modulations;
• wherein each modulation of the plurality of modulations comprises a constellation and a mapping;
• wherein the plurality of I associated outputs being indicative of I-axis distances separating an I component of the received symbol and a plurality of predetermined I coefficients corresponding to the constellation;
• and
• wherein the plurality of Q associated outputs being indicative of Q-axis distances separating a Q component of the received symbol and a plurality of predetermined Q coefficients corresponding to the constellation;
• and
• a plurality of min* processing blocks that processes selected I,Q sums according to the rate control sequence to generate a plurality of output metrics, wherein the selected I,Q sums comprising sums of an I associated output from the plurality of I associated outputs and a Q associated output from the plurality of Q associated outputs;
• and
• a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence.

A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:

• a plurality of sigma scaling blocks that scales an in-phase (I) component of the received symbol and a quadrature (Q) component of the received symbol based on a signal to noise ratio of the received symbol;
• a plurality of predetermined, scaled I coefficients that are scaled based on the signal to noise ratio of the received symbol;
• and
• a plurality of predetermined, scaled Q coefficients that are scaled based on the signal to noise ratio of the received symbol;
• a plurality of I summing blocks that selectively sums the scaled I component of the received symbol with each of the predetermined, scaled I coefficients thereby generating a plurality of I sums;
• a plurality of Q summing blocks that selectively sums the scaled Q component of the received symbol with each of the predetermined, scaled Q coefficients thereby generating a plurality of Q sums;
• a plurality of I squaring blocks that squares each I sum of the plurality of I sums thereby generating a plurality of squared I sums;
• a plurality of Q squaring blocks that squares each Q sum of the plurality of Q sums thereby generating a plurality of squared Q sums;
• a square output multiplexor that receives the plurality of squared I sums and the plurality of squared Q sums and outputs a plurality of I outputs and a plurality of Q outputs;
• a plurality of I,Q summing blocks that selectively sums the plurality of I outputs and the plurality of Q outputs from the square output multiplexor according to the rate control sequence thereby generating a plurality of I,Q outputs;
• a plurality of min* processing blocks that processes the plurality of I,Q outputs thereby generating a plurality of output metrics according to the rate control sequence;
• and
• a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence.

A metric generator method that calculates a metric associated with a received symbol according to a rate control sequence, the method comprising:

• calculating a plurality of in-phase (I) sums using an I component of a received symbol and a plurality of predetermined I coefficients;
• calculating a plurality of quadrature (Q) sums using a Q component of the received symbol and a plurality of predetermined Q coefficients;
• squaring each I sum of the plurality of I sums;
• squaring each Q sum of the plurality of Q sums;
• selectively summing an I sum of the plurality of I sums with a Q sum of the plurality of Q sums thereby generating a plurality of I,Q outputs according to the rate control sequence;
• performing min* processing on the plurality of I,Q outputs to generate a plurality of output metrics according to the rate control sequence;
• and
• outputting one metric from the plurality of output metrics according to the rate control sequence.