Symbol judgement apparatus, symbol judgement method and program

Abstract

The bit log-likelihood ratio generation unit generates a bit log-likelihood ratio of the reception symbol for each bit. The symbol selection unit selects a plurality of adjacent symbols of the reception symbol. A candidate sequence generation unit generates a plurality of candidate sequences by combining adjacent symbols of time-series reception symbols. The posterior probability maximum estimation unit calculates the log-likelihood ratio of the adjacent symbol to maximize the posterior probability using the output obtained by whitening time-series data of branched reception symbols and the candidate sequences reflecting the channel response. A likelihood ratio selection unit selects the bit log likelihood to be corrected based on the bit converted from the adjacent symbol. An addition unit performs weighted addition of the selected bit log-likelihood ratio and a correction value based on a difference between the bit log-likelihood ratio and the log-likelihood ratio.