Biasing schemes for storage of bits in unreliable storage locations

A non-volatile memory system comprising:

• non-volatile memory;
• and
• a controller configured to:
• bias, to a predetermined logic value using a biasing key, at least some of a first set of bits of a data set to be stored in memory elements of the non-volatile memory identified as unreliable;
• retrieve the data set from the non-volatile memory and load the data set into a random access memory during a read operation;
• assign, to a first set of bits of the data set stored in the identified unreliable memory elements, a first set of a plurality of log likelihood ratio values corresponding to a number of the first set bits of the data set stored in the identified unreliable memory elements;
• assign, to a second set of bits of the data set stored in identified reliable memory elements, a second set of the plurality of log likelihood ratio values corresponding to respective bit representations of the second set of bits;
• and
• in response to the data set loaded into the random access memory having at least one error, flip at least one sign bit of the plurality of log likelihood ratio values dependent on the first set of log likelihood ratio values corresponding to the number of the first set of bits of the data set stored in the identified unreliable memory elements.

A non-volatile memory system comprising:

• non-volatile memory;
• and
• means for biasing, to a predetermined logic value using a biasing key, a set of bits of a data set to be stored in memory elements of the non-volatile memory identified as unreliable during a write operation;
• means for storing the data set retrieved from the non-volatile memory during a read operation;
• means for assigning a plurality of log likelihood ratio values to the data set in the means for storing, wherein a set of the plurality of log likelihood ratio values, assigned to the set of biased bits, each correspond to a percent likelihood that a respective one of the set of biased bits was biased to the predetermined value using the biasing key;
• and
• means for flipping at least one sign bit of the plurality of log likelihood ratio values dependent on the set of log likelihood ratio values corresponding to the percent likelihood, in response to the data set in the means for storing having at least one error.