Hierarchical error correction code decoding using multistage concatenated codes

A method comprising:

• retrieving a codeword from a memory of a device;
• dividing the codeword into plurality of codeword blocks;
• decoding a codeword block of the plurality of codeword blocks using a middle coding scheme;
• determining that the decoding of the codeword block using the middle coding scheme failed;
• obtaining parity bits from other codeword blocks according to an outer coding scheme based on the determination that decoding the codeword block using the middle coding scheme failed;
• dividing the codeword block into a plurality of codeword rows;
• decoding a codeword row of the plurality of codeword rows using an inner coding scheme;
• and
• transmitting information bits of the codeword from the memory of the device based on decoding the codeword row.

An apparatus comprising:

• a memory device;
• an encoder configured to encode information for storage in the memory device using a hierarchical coding scheme including an outer coding scheme, a middle coding scheme, and an inner coding scheme;
• and
• a decoder configured to decode the information using the hierarchical coding scheme, wherein parity bits from the outer coding scheme are used when an error is detected in decoding a codeword block using the middle coding scheme, and wherein the inner coding scheme is used to decode codeword rows of the codeword block.