Precursor Inter-Symbol Interference Removal by Block Transmission Based Time-Reversed Equalization

In this paper, single-carrier transmission is considered in the general finite im- pulse response inter-symbol interference (ISI) channel. In an ISI channel with a matched filter, the folded spectrum of the received pulse can be factored into a minimum-phase causal part and a maximum-phase anticausal part corresponding to the postcursor and precursor ISI, respectively. In a direct implementation, the precursor equalization is carried out based on truncating and delaying the ideal anticausal precursor equalizer impulse response. In the proposed scheme, a block transmission is adopted, and the precursor equalization is carried out by a time reversal within each block and using a practical minimum-phase filter. We show that the ISI can be removed perfectly using the proposed technique. By means of a numerical example, it is shown that the proposed technique achieves improved performance compared to the truncate and delay based technique in terms of trans- mission rate, delay, and implementation complexity.