MMSE equalizer for MIMO-ISI channel with shortened guard period

An FIR MMSE equalizer (FIR-MMSEE) for block based transmission under the MIMO ISI channel is proposed in this paper. The proposed MMSE equalizer can get rid of the IBI problem without requiring a guard period which is not less than the channel order. By shortening the guard period, the bandwidth efficiency can be improved effectively especially for the channel with large dispersion. In addition, we further improve the BER performance of the FIR-MMSEE by propose a group successive interference cancellation MMSE equalizer (GSIC-MMSEE). In GSIC-MMSEE, a group of equalized outputs of the FIR-MMSEE is used to successively cancels their own effect in the received signals. This improves the error performance of the subsequent equalization. Moreover, because the interference cancellation is performed in group-by-group basis, the computation complexity can be controlled by adjusting the number of groups used. The performance of the FIR-MMSEE and GSIC-MMSEE was compared in the simulations.