Encoding device, memory controller, communication system, and encoding method

A memory controller comprising:

• a first candidate parity generation unit that generates, as a first candidate parity, a parity for detecting an error in an information section in which a predetermined value is assigned in a predetermined variable area;
• a second candidate parity generation unit that generates, as a second candidate parity, a parity for detecting an error in the information section in which a value different from the predetermined value is assigned in the predetermined variable area;
• a selection unit that selects a parity that satisfies a predetermined condition from among the first and second candidate parities as a selection parity;
• an output unit that outputs a codeword constituted by the information section corresponding to the selection parity and the selection parity to a memory cell as write data;
• and
• a decoding unit that reads read data from the memory cell and decodes the read data,
• wherein the information section includes user data input to the first candidate parity generation unit and unused data including the predetermined variable area.

A communication system comprising:

• a first candidate parity generation unit that generates, as a first candidate parity, a parity for detecting an error in an information section in which a predetermined value is assigned in a predetermined variable area;
• a second candidate parity generation unit that generates, as a second candidate parity, a parity for detecting an error in the information section in which a value different from the predetermined value is assigned in the predetermined variable area;
• a selection unit that selects a parity that satisfies a predetermined condition from among the first and second candidate parities as a selection parity;
• an output unit that outputs a codeword constituted by the information section corresponding to the selection parity and the selection parity as a transmission word;
• and
• a decoding unit that receives a received word corresponding to the transmission word to decode,
• wherein the information section includes user data input to the first candidate parity generation unit and unused data including the predetermined variable area.

An encoding method comprising:

• a first candidate parity generation procedure of generating, as a first candidate parity, a parity for detecting an error in an information section in which a predetermined value is assigned in a predetermined variable area;
• a second candidate parity generation procedure of generating, as a second candidate parity, a parity for detecting an error in the information section in which a value different from the predetermined value is assigned in the predetermined variable area;
• a selection procedure of selecting a parity that satisfies a predetermined condition from among the first and second candidate parities as a selection parity;
• and
• an output procedure of outputting a codeword constituted by the information section corresponding to the selection parity and the selection parity,
• wherein the information section includes user data input to the first candidate parity generation procedure and unused data including the predetermined variable area.