Signal decoding method and device, and signal storage system

A signal storage system having a write channel and a read channel, wherein

• the write channel comprises:
• a first encoder for run-length encoding of data;
• a second encoder for further encoding data encoded by the first encoder, using a low density parity check code;
• and
• a writing unit for writing the data encoded by the second encoder, to the storage device;
• the read channel comprises:
• a reading unit for reading the data encoded by the second encoder, from the storage device;
• a soft output detection unit for calculating likelihood for the data read by the reading unit and for outputting a soft decision value;
• a second decoder, corresponding to the second encoder, for decoding the data outputted from the soft output detection unit;
• and
• a first decoder, corresponding to the first encoder, for further decoding the data decoded by the second decoder;
• and wherein
• the second decoder has a unit decoder that, when the data outputted from the soft output detection unit is decoded, performs multiplication of the decoded data by a matrix;
• if s and t are natural numbers, s≧t≧2, the unit decoder uses a matrix in which, among s columns extracted from the matrix, t columns or less have a linearly independent relationship;
• and
• the s columns are multiplied by a portion of the decoded data in which error occurrence frequency is relatively high.

A signal storage system having a write channel and a read channel, wherein

• the write channel comprises:
• a first encoder for run-length encoding of data;
• a second encoder for further encoding data encoded by the first encoder, using a low density parity check code;
• and
• a writing unit for writing the data encoded by the second encoder to the storage device;
• the read channel comprises:
• a reading unit for reading the data encoded by the second encoder, from the storage device;
• a soft output detection unit for calculating likelihood for the data read by the reading unit and for outputting a soft decision value;
• a second decoder, corresponding to the second encoder, for decoding the data outputted from the soft output detection unit;
• and
• a first decoder, corresponding to the first encoder, for further decoding the data decoded by the second decoder;
• and wherein
• the second decoder has a unit decoder that, when the data outputted from the soft output detection unit is decoded, performs multiplication of the decoded data by a matrix;
• if s and t are natural numbers, s≧t≧2, the unit decoder uses a matrix in which, among s columns extracted from the matrix, t columns or less have a linearly independent relationship;
• and
• the s columns are adjacent in the matrix.