List-decoding of parity-sharing Reed-Solomon codes in magnetic recording systems

An (n,k) Reed-Solomon (RS) code is used in a magnetic recording system to help reduce the word failure rate (WFR). If the channel signal-to-noise ratio (SNR) exceeds a certain value, the full power of a given RS code may be needed only on a few occasions to guarantee a target WFR. When this occurs, a parity-sharing scheme can be used to group a number of RS codewords into a larger codeword, block. The target WFR can, therefore, be achieved at a higher code rate. An efficient list-decoding technique has recently been developed by Guruswami and Sudan (G-S) that allows error correction beyond the classical "half-the-minimum-distance" bound. Koetter and Vardy (K-V) have further extended the G-S algorithm to perform soft-decision list-decoding. This work will show that G-S hard-decision and K-V soft-decision list-decoding of parity-sharing codes are both effective and computationally manageable schemes on the discrete memoryless and partial response channels.