Concatenated error correcting codes

A method, comprising:

• reading bits of a Low-Density Parity-Check (LDPC) codeword from a non-volatile storage device, the LDPC codeword being generated by LDPC encoding a Bose-Chaudhuri-Hocquenghem (BCH) codeword, the BCH codeword being generated by BCH encoding a data unit;
• feeding the bits of the LDPC codeword read from the non-volatile storage device to an LDPC decoder;
• and
• performing an iterative concatenated decoding process on the LDPC codeword in an iterative LDPC decoding process;
• wherein performing the iterative concatenated decoding process comprises performing a first iteration comprising:
• performing a first LDPC decoding iteration of the iterative LDPC decoding process on the LDPC codeword to generate a first intermediate LDPC decoding result;
• determining a first LDPC syndrome of the first intermediate LDPC decoding result has not reached zero;
• determining whether a triggering condition for BCH decoding is met using a BCH scheduler, wherein the triggering condition for BCH decoding is based on status information of the iterative LDPC decoding process;
• in response to the triggering condition for BCH decoding being met, performing a BCH decoding process on the first intermediate LDPC decoding result;
• in response to the triggering condition for BCH decoding not being met, performing a second iteration in the iterative concatenated decoding process;
• wherein the second iteration starts with performing a second LDPC decoding iteration of the iterative LDPC decoding process on the LDPC codeword to generate a second intermediate LDPC decoding result;
• wherein the second iteration continues by:
• determining a second LDPC syndrome of the second intermediate LDPC decoding result has not reached zero;
• determining whether the triggering condition for BCH decoding is met using the BCH scheduler;
• in response to the triggering condition for BCH decoding being met, performing the BCH decoding process on the second intermediate LDPC decoding result;
• in response to the triggering condition for BCH decoding not being met, performing a third iteration in the iterative concatenated decoding process;
• wherein the third iteration starts with performing a third LDPC decoding iteration of the iterative LDPC decoding process on the LDPC codeword to generate a third intermediate LDPC decoding result.