A Family of Equalizers for Optimal Sequence Detection

We present a family of equalizers and targets for certain intersymbol interference (ISI) channels with the property that the performance of a maximum-likelihood (ML) or maximum a posteriori (MAP) based detector for the target channel is also simultaneously optimal for the equalized channel. In particular, the MMSE decision feedback equalizer (DFE) belongs to this family of filters. Although, these solutions are infinite impulse response (IIR) filters, we can achieve good performance using finite impulse response (FIR) filters. We present an algorithm for designing equalizers and FIR targets that minimize the probability of sequence detection error