| 摘要 |
PROBLEM TO BE SOLVED: To provide a decoding method, apparatus and program for decoding low density parity check code data whereby the computational complexity of the whole decoding apparatus is reduced by reducing the computational complexity of a check node to attain a high speed and low power consumption as the Sum-Product decoding applied to low density parity (LPDF) code data. SOLUTION: The decoding method has a check matrix H (n-columns, m-rows) and uses the Sum-Product decoding for iteratively calculating the Gallager's function f(x). The method calculates distances between a minimum argument x<SB>min</SB>and each of the other arguments (x) in a non-zero variable node set A(m) for each of (m) rows in the check matrix H. Next, in accordance with the distances between the minimum argument x<SB>min</SB>and the plurality of other arguments (x), a threshold value (d) is determined. Only arguments (x) with distances equal to or less than the threshold value (d) are selected and partial sets C(m) with respect to the variable node set A(m) are derived. Thereafter, the method iterates the function f(x) for the variable node partial sets C(m) to update a logarithm external value ratioαmn in the check node processing. COPYRIGHT: (C)2008,JPO&INPIT
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