Device for encoding and decoding using smaller block of symbols

Abstract

A method of encoding user data into codevectors of an error correcting code, includes generating a first block of data symbols including user data symbols and dummy data symbols; encoding the first block using an ECC encoder to obtain a codeword comprising the first block of data symbols and a second block of parity symbols; and generating a codevector by selecting a user data portion of the user data symbols from the first block and a parity portion of the parity symbols from the second block. The sum of a number of the user data portion and a number of the parity portion is smaller than the sum of a number of the user data symbols and a number of the parity symbols of the second block.

1 . A device for encoding an information word into a codeword, the device comprising:
 an encoder configured to receive the information word and a matrix, the encoder being further configured to encode the information word comprising k information symbols using the matrix comprising k rows and n+k columns for output of an intermediate codeword having k+n symbols; and   a codeword generator configured to receive the intermediate codeword and output the codeword by omitting a number of symbols of the intermediate codeword.   
     
     
         2 . The device of  claim 1 , wherein each column of the k columns of the matrix includes a single non-zero entry at a mutually different position than other columns of the k columns. 
     
     
         3 . The device of  claim 1 , wherein the number of symbols omitted from the intermediate codeword corresponds to a difference between a number of columns of the matrix, being n+k columns, and a precursor matrix from which the matrix had been generated by increasing a number of columns of the precursor matrix, being n columns, by k columns, resulting in the codeword having n symbols. 
     
     
         4 . A device for decoding a codeword for output of an information word, the device comprising:
 an extender configured to receive the codeword comprising n symbols and to extend the codeword by adding k erasures for output of a first pseudo codeword having a length determined based on a matrix used by an encoder to form the codeword;   a replacement unit configured to replace the k erasures of the first pseudo codeword with known information symbols for output of a second pseudo codeword; and   a decoder configured to receive the second pseudo codeword and the matrix and decode the second pseudo codeword using the matrix into the information word comprising k symbols.   
     
     
         5 . The device of  claim 4 , wherein a number of symbols of the first pseudo codeword corresponds to a number of columns of the matrix.