Decoders, decoding methods, memory controllers and memory systems

A memory system comprising:

• a memory controller;
• and
• a memory device coupled to the memory controller;
• wherein the memory controller comprises a decoder, wherein a check matrix corresponding to a frame of code words comprises a*a sub-matrices, a plurality of sub-matrices located in the same row in the check matrix constitute a layer of the check matrix, and a plurality of sub-matrices located in the same column constitute a column of the check matrix, the decoder comprising:
• a check node updating circuit that comprises first updating units of a levels, wherein the first updating unit of each level is connected sequentially;
• and
• a variable node updating circuit that is connected with the check node updating circuit, the variable node updating circuit comprises second updating units of a levels, wherein the second updating unit of each level is connected sequentially;
• wherein,
• in a first time period, the check node updating circuit is configured to cause:
• the first updating unit of each level except the first updating unit of a first level sequentially receive variable node messages corresponding to each column of the check matrix, and sequentially calculate the received variable node messages with messages in the first updating unit of a previous level, to obtain the check node messages corresponding to different layers of the check matrix in the first updating units of different levels in the first updating units of a levels;
• in the first time period, the variable node updating circuit is configured to cause:
• the second updating unit of the a-th level sequentially receive the variable node messages corresponding to each column of the check matrix, and the second updating unit of each level except the second updating unit of the a-th level sequentially receive the messages of the second updating unit of a next level and performing calculation, to obtain corresponding intermediate calculation values in the second updating units of different levels in the second updating units of a levels;
• and
• in a second time period after the first time period, the variable node updating circuit is configured to cause:
• the second updating unit of each level except the second updating unit of the a-th level sequentially receive the check node messages corresponding to each layer of the check matrix, and sequentially calculate the received check node messages with the intermediate calculation values of the second updating unit of the next level, to obtain the variable node messages corresponding to different columns of the check matrix in the second updating units of different levels in the second updating units of a levels.

A decoding method, wherein during decoding a frame of code words with a check matrix including a*a sub-matrices, a plurality of sub-matrices located in the same row in the check matrix constitute a layer of the check matrix, and a plurality of sub-matrices located in the same column constitute a column of the check matrix, the method comprising:

• in a first time period, first updating unit of each level except the first updating unit of a first level sequentially receiving variable node messages corresponding to each column of the check matrix, and sequentially calculating the received variable node messages with messages in the first updating unit of a previous level, to obtain the check node messages corresponding to different layers of the check matrix in the first updating units of different levels in the first updating units of a levels;
• in the first time period, the second updating unit of the a-th level sequentially receiving the variable node messages corresponding to each column of the check matrix, and the second updating unit of each level except the second updating unit of the a-th level sequentially receiving the messages of the second updating unit of a next level and performing calculation, to obtain corresponding intermediate calculation values in the second updating units of different levels in the second updating units of a levels;
• and
• in a second time period, the second updating unit of each level except the second updating unit of the a-th level sequentially receiving the check node messages corresponding to each layer of the check matrix, and sequentially calculating the received check node messages with the intermediate calculation values of the second updating unit of the next level, to obtain the variable node messages corresponding to different columns of the check matrix in the second updating units of different levels in the second updating units of a levels.