MLSE equalizer structures for space-time coding in frequency selective channel

Space-time coding has been proposed as a coding scheme for multiple-input multiple output (MIMO) antenna systems. However, when the delay spread of the MIMO channel is too large there is significant performance degradation and there is a need for equalization. In this paper we use MLSE structures that decode the space-time codes and equalize the channel in one structure. The resulting complexity of MLSE is therefore increased and it is necessary to took at ways to minimize this. Here we compare the Forney and Ungerboeck forms and we find that the Ungerboeck form is more attractive. In particular its complexity does not depend on the number of receive antennas.