Forward error correction (fec) convergence by controlling reliability levels of decoded words in a soft fec decoder

A method comprising:

• receiving, from an optical receiver and by a device, a plurality of words, each of the plurality of words including a plurality of samples, where each of the plurality of samples includes:
• a corresponding one of a plurality of encoded bits, and
• respective reliability bits for identifying a respective level of reliability of the corresponding one of the plurality of encoded bits;
• identifying, by the device and within a first word of the plurality of words, a set of least reliable encoded bits having levels of reliability that are less than a reliability threshold, where the first word includes different versions with different combinations of inverted bits within the set of least reliable encoded bits;
• generating, by the device, a set of candidate words based on the different versions of the first word;
• decoding, by the device, the set of candidate words to create a set of decoded words;
• comparing, by the device, the set of decoded words to the first word to identify measures of similarity between the set of decoded words and the first word;
• selecting, by the device and as a second word, one of the set of decoded words that includes a greatest measure of similarity among the identified measures of similarity;
• identifying, by the device, a quantity of errors, associated with the first word, based on the comparison of the second word to the first word;
• determining, by the device, whether the quantity of errors is greater than a threshold;
• outputting, by the device, a third word based on a first version of the first word that includes a higher level of reliability than the first word when the quantity of errors is not greater than the threshold;
• or
• outputting, by the device, a fourth word based on a second version of the first word that includes a lower level of reliability than the first word when the quantity of errors is greater than the threshold.

A device comprising:

• a memory to store a block of words that are generated as a result of a one or more iterations associated with an error correction operation, where each word of the block of words, includes respective encoded bits and respective sets of reliability bits that identify a respective level of reliability of each one of the respective encoded bits;
• and
• one or more components to:
• receive an instruction to perform an another iteration associated with the error correction operation,
• obtain, in response to the instruction, a first word, from the block of words, associated with a previous one of the one or more iterations,
• process the first word, to create one or more decoded versions of the first word,
• where measures of similarity, between the first word and the one or more decoded versions of the first word, are provided,
• select, as a second word, one of the one or more decoded versions of the first word associated with a highest one of the measures of similarity,
• determine a quantity of errors within the first word based on a comparison of the first word to the second word,
• determine whether the quantity of errors is greater than a threshold,
• generate, based on the first word, a third word when the quantity of errors is not greater than the threshold, where the third word includes a first set of bits, each having a level of reliability that is greater than or equal to a corresponding one of a second set of bits within the first word,
• generate, based on the first word, a fourth word when the quantity of errors is greater than the threshold, where the fourth word includes a third set of bits, each having a lower level of reliability than the corresponding one of the second set of bits, and
• output the third word or the fourth word based on whether the quantity of errors is greater than the threshold.