Data reading method, storage controller and storage device

A storage controller, configured to control a storage device having a rewritable non-volatile memory module, the storage controller comprising:

• a connection interface circuit, configured to couple to a host system;
• a memory interface control circuit, configured to couple to the rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of word lines, wherein each word line among the word lines is coupled to a plurality of memory cells, wherein each memory cell among the memory cells comprises a plurality of physical pages, and each physical page among the physical pages is configured to be programmed as a bit value;
• a read assisting circuit unit;
• an error checking and correcting circuit;
• and
• a processor, coupled to the connection interface circuit, the memory interface control circuit, the read assisting circuit unit and the error checking and correcting circuit,
• wherein the processor is configured to select a target word line among the word lines of the rewritable non-volatile memory module, and perform a read operation on the target word line,
• wherein the read assisting circuit unit is configured to use a preset read voltage set to read a plurality of target physical pages of the target word line, so as to obtain a plurality of hard bit codewords respectively corresponding to the target physical pages,
• wherein the read assisting circuit unit is further configured to generate soft information of each of a plurality of target memory cells of the target word line according to the hard bit codewords,
• wherein the read assisting circuit unit is further configured to identify a plurality of confidence values corresponding to the target physical pages of each of the target memory cells according to a plurality of confidence tables respectively corresponding to the target physical pages and the soft information of the target memory cells, wherein each of the confidence tables has a plurality of preset confidence values respectively corresponding to a plurality of threshold voltage distribution regions, wherein the threshold voltage distribution regions correspond to a plurality of gray code patterns,
• wherein the error checking and correcting circuit is configured to use the confidence values of the target memory cells to replace a plurality of log-likelihood ratios corresponding to the target memory cells in a preset decoding operation, and perform an adjusted preset decoding operation having the replaced log-likelihood ratios on the soft information, so as to obtain a plurality of final decoded codewords respectively corresponding to the target physical pages and thereby complete the read operation.

A storage device, the storage device comprising:

• a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of word lines, wherein each of the word lines is coupled to a plurality of memory cells, wherein each memory cell among the memory cells comprises a plurality of physical pages, and each physical page among the physical pages is configured to be programmed as a bit value;
• a memory interface control circuit, configured to couple to the rewritable non-volatile memory module;
• and
• a processor, coupled to the memory interface control circuit, wherein the processor loads in and execute a read assisting program code module to realize a data reading method, and the data reading method comprises steps of:
• selecting a target word line, and performing a read operation on the target word line;
• using a preset read voltage set to read a plurality of target physical pages of the target word line, so as to obtain a plurality of hard bit codewords respectively corresponding to the target physical pages;
• generating soft information of each of a plurality of target memory cells of the target word line according to the hard bit codewords;
• identifying a plurality of confidence values corresponding to the target physical pages of each of the target memory cells according to a plurality of confidence tables respectively corresponding to the target physical pages and the soft information of the target memory cells, wherein each of the confidence tables has a plurality of preset confidence values respectively corresponding to a plurality of threshold voltage distribution regions, wherein the threshold voltage distribution regions correspond to a plurality of gray code patterns;
• and
• using the confidence values of the target memory cells to replace a plurality of log-likelihood ratios corresponding to the target memory cells in a preset decoding operation, and performing an adjusted preset decoding operation having the replaced log-likelihood ratios on the soft information, so as to obtain a plurality of final decoded codewords respectively corresponding to the target physical pages and complete the read operation.