Concatenating a Structured LDPC Code and An RLL Code to Preserve Soft-Decoding, Structure, and Burst Correction

Error-control codes and runlength limited codes each provide critical roles in maintain data integrity on storage devices,with ECCs doing directly by inserting redundancy via some encoding algo-rithm,and RLL codes doing indirectly by facilitating timing recovery.In this paper,we add another two requirements to the RLL-LDPC concatenation.First,we require the LDPC code possess structure to facilitate encoder and decoder. Second,the nominal H matrix of the LDPC code must be modified to accommodate both the RLL constraint and the ability to correct long bursts[6].