Performance improvement of a decision-feedback equalizer in terrestrial dtv receivers by reduction of error propagation

Abstract

This paper presents a novel equalization methodfor ATSC terrestrial digital televi.sion (DTV) receivers by incorporating a channel-matched filter (CMF) and an intelligent slicer. Decbion f’cedback ey7iulizer.s (DFEs) have been generally used for ATSC DTV receivers but .stflevfboni error propagation occurying in severe ghosts andor low signal-to-noise rario (SNR) conditions. Severe channel properties. such as a 0-dB ghost, become manageable in the DFE by the use ofthe CMFprior to the DFE. The intelligent .slicer which is a trellis decoder wit17 a trace-hack depth of I enhatices correct-decision probabilih/ in 1/7e DFE, especiallv under low SNR conditions. The adoption oJtlie CMF and the intelligent slicer makes the DFE deal with ,severe ghosts under low SNR conditions b. reducing error propagation. In addition. an initialization scheme of’ the DFE tap coeflkients is used to overcome the shortness of the training sequence and speed up the convergence of’the DFE. Simulation results shon that the proposed method is more efective and more stable than exi.sting methods in severe channels, such a.s a 0 dB mziltipatli condition. Index Terms Channel-matched filter, decision-feedback equalizer, DTV.