Systems and methods for error correction and decoding on multi-level physical media

Abstract

Apparatus and methods for operating a flash device characterized by use of Lee distance based codes in a flash device so as to increase the number of errors that can be corrected for a given number of redundancy cells, compared with Hamming distance based codes.

What is claimed is: 
     
         1 . A method for operating a flash device, said method comprising: providing a Lee code associated with a first group of symbols; and programming data in the flash device using a second group of symbols, said second group being a sub group of the first group so as to allow extending the number of errors that can be corrected for a given number of redundancy cells compared with Hamming distance based codes. 
     
     
         2 . The method of  claim 1  wherein said first data stream is associated with a first group of symbols and said redundancy data stream is associated with a second group of symbols, said second group being a sub group of the first group. 
     
     
         3 . A decoding system comprising: a Lee metric-based decoder operative to decode multi-level physical media. 
     
     
         4 . A method for error correction comprising: encoding data capable of being decoded, thereby to effect error correction, said encoding comprising using a separate encoder to store a Syndrome computation to be used during said decoding. 
     
     
         5 . A system according to  claim 3  wherein said multi-level physical media includes media having less levels than symbol values. 
     
     
         6 . A method for error correction comprising: encoding data capable of being decoded, thereby to effect error correction, said encoding comprising: encoding a syndrome giving rise to encoded syndrome; and encapsulating and mapping the encoded syndrome into designated media cells. 
     
     
         7 . A method for error correction comprising: encoding data capable of being decoded, thereby to effect error correction, said encoding comprising: encoding a syndrome; and reducing error probability in the encoded Syndrome by encapsulating and mapping the encoded Syndrome mixed with data bits into designated media cells.