DOUBLE BIT ERROR CORRECTION IN A CODE WORD WITH A HAMMING DISTANCE OF THREE OR FOUR

摘要

A method for determining the erroneous bits in an initial binary word affected by a double error and arising from a code endowed with a minimum Hamming distance equal to 3 or 4 comprises reception of a datum indicative of a binary level of confidence, low or high, assigned to each of the bits of at least one part of the initial word, a step of generating the syndrome on the basis of the initial word and a step of determining whether the syndrome is that of a code word affected by a double error, in which if it identifies, on the basis of the syndrome, an error in the initial word whose two affected bits correspond to bits of low confidence in the initial word, the two erroneous bits are selected to be corrected. The method applies notably to the fields of error correcting codes and nanometric technologies.

主权项

1. A method for determining the erroneous bits in an initial binary word affected by a double error and arising from a code endowed with a minimum Hamming distance equal to 3 or 4, comprising the reception of a datum indicative of a binary level of confidence, low or high, assigned to each of the bits of at least one part of the initial word, the method comprising a step of generating the syndrome on the basis of the initial word and a step of determining whether said syndrome is that of a code word affected by a double error, comprising at least the following steps:
a test step on the number of bits with a low confidence level in the initial word if the test indicates that said initial word contains more than one bit suffering a low confidence level, then a third step is executed, does there exist a pair {code word, double error}, for which the code word affected by this double error generates said syndrome, and for which the two bits affected by the error correspond to bits whose confidence level is signaled as low in said initial word, if yes then a double error in said initial word whose two affected bits correspond to bits of low confidence in said initial word is chosen on the basis of said syndrome, said two erroneous bits are selected so as to be corrected, if the test indicates that said initial word does not contain more than one bit with a low confidence level, a step is executed which performs the following test: does there exist a pair {code word, double error}, for which the code word affected by this double error generates said syndrome, and for which one bit out of the two bits affected by the error corresponds to the bit whose confidence level is signaled as low in said initial word, if no double error generating said syndrome affects two bits of low confidence in said initial word, then a double error, for which one of the two bits affected is a bit of low confidence in said initial word, is identified.