MMSE Equalizer for MIMO-ISI Channel With Shorten Guard Period

A finite-impulse-response minimum mean-square error equalizer (FIR-MMSEE) for block-based transmission over a multiple-input multiple-output (MIMO) intersymbol interference (ISI) channels is proposed in this correspondence. The proposed MMSE equalizer can avoid interblock interference (IBI) without requiring a guard period to be larger than or equal to the channel order. By reducing the number of redundant symbols in the transmitted signals, the spectral efficiency of the communication system with long channel dispersion can be greatly improved. We further investigated the parallel FIR-MMSEE equalization structure and proposed a group successive interference cancellation MMSE equalizer (GSIC-MMSEE). A group of elements in the output of the FIR-MMSEE will be used to successively cancel their own effect in the received signals after the signal detection in GSIC-MMSEE. Since the cancellation process eliminates some interference sources, the error performance of the subsequent equalization will be improved. Moreover, the interference cancellation is performed in a group-by-group basis. As a result, the computational complexity of the proposed equalizer can be controlled by adjusting the number of groups in the GSIC. Simulation results are presented to compare the performance of the proposed FIR-MMSEE and GSIC-MMSEE