Error performance of mismatched receivers for linear-coded modulation

Optimum demodulation of intersymbol interference may be performed using maximum-likelihood sequence estimation receivers. Standard performance analysis of these receivers assume that the receiver has perfect knowledge of the channel. We assume instead a mismatched receiver that uses an imperfect estimate of the channel to decode the information sequence. A free-distance expression for a mismatched ML receiver is derived and applied to the case of linear-coded modulation. A truncated union bound approximation accurately predicts the error probability.