Decoder, and memory system for obtaining an updated posterior messages corresponding to a non-zero sub-matrix

A memory system, comprising:

• a memory device configured to output read data;
• and
• a decoder, comprising:
• a first memory;
• and
• a message updating circuit,
• wherein the first memory is configured to store posterior probability messages,
• wherein the message updating circuit is configured to:
• sequentially read a posterior probability message corresponding to each non-zero sub-matrix of a current layer from the first memory in a first reading order, the first reading order being determined according to a position of each non-zero sub-matrix of the current layer;
• obtain an updated posterior probability message corresponding to each non-zero sub-matrix of the current layer based on the posterior probability message corresponding to each non-zero sub-matrix of the current layer in a current iteration;
• and
• sequentially write the updated posterior probability message corresponding to each non-zero sub-matrix of the current layer into the first memory in a first writing order, the first writing order being determined according to the first reading order, and
• wherein the decoder is configured to decode a codeword to be decoded in the read data.

A method of decoding, comprising:

• sequentially reading a posterior probability message corresponding to each non-zero sub-matrix of a current layer from a first memory in a first reading order, the first reading order being determined according to a position of each non-zero sub-matrix of a current layer;
• obtaining an updated posterior probability message corresponding to each non-zero sub-matrix of the current layer based on the posterior probability message corresponding to each non-zero sub-matrix of the current layer in a current iteration;
• and
• sequentially writing the updated posterior probability message corresponding to each non-zero sub-matrix of the current layer into the first memory in a first writing order, the first writing order being determined according to the first reading order.