SOFT OUTPUT DECODER AND SOFT OUTPUT DECODING METHOD AND DECODER AND DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To achieve high rate processing in decoding a code having a parallel path while reducing the burden of processing without sacrifice of performance. SOLUTION: A soft output decoding circuit 90 in an element decoder comprises a circuit 157 for distributing a logarithmic likelihood Iγrepresenting the probabilityγdetermined by the output pattern and receiving value of a code logarithmically for each receiving value such that it corresponds to a branch on a trellis depending on the configuration of a code. The Iγdistribution circuit 157 comprises a parallel path processing circuit 2251 for Iβ0 bundling the logarithmic likelihood Iγcorresponding to a parallel path, a parallel path processing circuit 2252 for Iβ1 and a parallel path processing circuit 2253 for Iαwhich are used at the time of decoding a code having a parallel path where the origin of transition has the same state the destination of transition has the same state.