Decoder and decoding method

摘要

A decoder has a reduced circuit dimension that does not adversely affect the decoding performance of the circuit. The decoder includes an addition/comparison/selection circuit added to give the log likelihood and adapted to compute a correction item expressed in a one-dimensional function relative to a variable and add a predetermined value to the correction term in order to provide a unified symbol for identifying the positiveness or negativeness of the log likelihood for the purpose of computing the log likelihood.