Frequency-domain equalization for distributed terrestrial DTV transmission environments

The 8-VSB modulation, the transmission standard for the terrestrial digital television (DTV) of the Advanced Television Systems Committee (ATSC), suffers from multipath fading because it conveys information on the amplitude. To solve this problem, decision feedback equalizers (DFEs) have been commonly used in the terrestrial DTV receivers. However, under severe channels, such as a 0-dB ghost channel or a distributed transmission environment, the DFEs have shown unstable convergence due to the error propagation caused by decision errors. Instead of unstable time-domain DFE schemes, by proposing a frequency-domain direct-inversion equalization method, we achieve stable equalization and low symbol error rates. To secure the existence of a channel inverse, channel-matched filtering and noncausal filtering are carried out before equalization. Simulation results show that the proposed method performs much better than the existing DFE schemes in terms of both the stability and the symbol error rates.