Performance evaluation of the mean-square prefiltered delayed decision feedback sequence detector

In signal equalization, a technique that allows reduction of the number of states of the Viterbi detector is the delayed decision feedback sequence detector (DDFSD). In order to achieve good performance, it is essential to operate, before the DDFSD, an appropriate prefiltering of the received sequence. This paper is devoted to performance evaluation of the DDFSD when the feedforward filter of a minimum mean square error decision feedback equalizer is adopted as a prefilter. A truncated version of the union bound is used to approximate the bit error rate. The analysis includes a method for determining the error events that dominate the bound.