A list-output Viterbi equalizer with two kinds of metric criteria

This paper proposes a list-output Viterbi equalizer (LVE) for wide-spread time-dispersive channels, which uses two kinds of metric criteria, in order to achieve a good trade-off between complexity and bit error rate (BER) performance. For the Viterbi equalization employing a state-reduction algorithm, the modified metric proposed by Ungerboeck (1974) is not always equivalent to the squared Euclidean distance. This paper proposes the following two LVEs: (1) to combine two kinds of metric criteria; (2) to select the metric criterion according to the channel impulse response. Finally, computer simulation shows that the proposed scheme improves the BER performance on frequency selective fading channels, even if the proposed scheme has smaller complexity than the conventional one.