DECODER AND DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To decode an LDPC (low density parity check) code with high accuracy by improving encoding performance by optimizing a quantization width. SOLUTION: A decoder 3 is provided with a variance measuring section 20 for finding the dispersion of noises overlapped on data received by a receiving section 10; a quantization width determining section 30 for determining a quantization width which is optimized so that an error probability after decoding becomes the smallest for the dispersion of noises found by the section 20 or so that the dispersion of noises found by the section 20 becomes the largest for the provided decoded error probability; a quantization section 40 for quantizing the probability distribution of a reception value received by the section 10 at a predetermined low bit number determined by the section 30; and a message computing section 50 for computing a message as an information bit on the basis of probability distribution of the reception value quantized by this section 40. COPYRIGHT: (C)2004,JPO