A ROBUST VITERBI DECODER AND ITS APPLICATION TO TERRESTRIAL HDTV BROADCASTING

The conventional Viterbi decoder employing Euclidean distance has been widely used and considered as the optimum one in the sense of maximum likelihood sequence decoding under the hypothesis of additive white G aussian noise (AWGN). However, what will happen if the noise distribut ions of actual channels deviate from the assumed AWGN? A robust Viterb i decoder utilizing absolute distance is carefully examined in this pa per. Analytical and numerical results show that this Viterbi decoder i s more advantageous than the conventional Viterbi decoder for actual c hannels with various kinds of interferences, particularly in the prese nce of impulsive noise. Finally the robust Viterbi decoder is applied to TCM-8VSB terrestrial HDTV broadcasting, achieving 0.5 - 1.0 dB SNR gains over the conventional Viterbi decoder on contaminated AWGN chann els.