Method and apparatus for iteratively improving the performance of coded and interleaved communication systems

A system for determining channel equalization factors applied to a digital channel equalizer to improve reception performance of a signal transmitted over a digital communication channel, comprising:

• means to iteratively determine at least one estimate associated with a decision of a received signal corresponding to said transmitted signal wherein said means to iteratively determine includes combining a current decision with a previous decision in a predetermined manner;
• means to iteratively modulate said at least one estimate;
• means to iteratively determine said equalization factors dependent upon said received signal and said modulated estimate,
• means to iteratively update a channel estimate as a function of said equalization factors;
• and
• means to iteratively modify an equalizer to utilize said channel estimate;
• wherein said means to literatively modulate comprises an encoder, an interleaver, and a modulator.

A method for improving reception performance of a signal transmitted over a digital communication channel comprising the steps of:

• a. demodulating a received signal having frames of known and unknown symbols to produce demodulated data;
• b. equalizing the demodulated data with an equalizer to produce a plurality of equalized symbols;
• c. determining at least one estimate from said equalized symbols, the at least one estimate associated with a decision of the received signal corresponding to the transmitted signal;
• d. using the at least one estimate to update a channel estimate for at least one frame;
• e. modifying the equalizer to utilize an estimate of computed symbols;
• f. computing bit soft decisions from the estimate of computed symbols;
• g. deinterleaving the computed bit soft decisions;
• h. averaging deinterleaved bit soft decisions with previous soft decisions;
• and
• i. iteratively repeating steps (a)-(h) for a predetermined number of iterations.