Optimum equalizer for coherent radio receivers

A method is presented to determine the optimum equalizer for coherent communication systems in terms of minimum mean square error (MMSE). Two well-known T-spaced equalizer structures have been considered: the linear trasversal equalizer (LTE) and the decision feedback equalizer (DFE). The method is based on a numerical evaluation of the MMSE as a function of the equalizer delay and complexity. Both the LTE and DFE are compared in the presence of radio channel examples assuming perfect channel estimation and synchronization.