Method and apparatus for reliable resynchronization of sequential decoders

A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for resynchronization of a sequential decoder which decodes received signal samples stored within an input buffer comprising when the input buffer reaches a threshold saturation level, the steps of:

• a) stopping the sequential decoding process;
• b) running a forward pass of a MAP decoding process on a first sequence of the signal samples to compute first a posteriori probabilities of information bits associated with the first sequence of the signal samples and to estimate a first resynchronization state;
• c) using the first a posteriori probabilities to determine a first reliability value of the first resynchronization state,
• d) if the first reliability value is greater than a first reliability threshold value, restarting the sequential decoding process at the first resynchronization state, otherwise:
• e) running a forward pass of a MAP decoding process on a second sequence of the signal samples to compute second a posteriori probabilities of information bits associated with the second sequence of signal samples and to estimate a second resynchronization state;
• f) using the second a posteriori probabilities to determine a second reliability value of the second resynchronization state;
• g) if the second reliability value is greater than a second reliability threshold value, restarting the sequential decoding process at the second resynchronization state;
• otherwise
• h) repeating steps e) through h).

A sequential decoding system for resynchronizing a sequential decoder which decodes received signal samples stored in an input buffer, said system comprising:

• when the input buffer reaches a threshold saturation level
• a) means for stopping the sequential decoding process;
• b) means for running a forward pass of a MAP decoding process on a first sequence of the signal samples to compute a first a posteriori probabilities of information bits associated with the first sequence of the signal samples and to estimate a first resynchronization state;
• c) means for using the first a posteriori probabilities to determine a first reliability value of the first resynchronization state;
• d) means for, if the first reliability value is greater than a first reliability threshold value, restarting the sequential decoding process at the first resynchronization state, otherwise for:
• (i) running a forward pass of a MAP decoding process on a second sequence of the signal samples to compute a second a posteriori probabilities of information bits associated to the second sequence of signal samples and to estimate a second resynchronization state,
• (ii) using the second a posteriori probabilities to determine a second reliability value of the second resynchronization state,
• (iii) if the second reliability value is greater than a second reliability threshold value, restarting the sequential decoding process at the second resynchronization state, otherwise, if the second reliability value is less than or equal to a second reliability threshold value, repeating steps d(i) through d(iii).