Design and implementation of frequency domain equalizer for ATSC system

Multi-path interference, presents one major challenge for ATSC (Advanced Television Systems Committee) equalizer design, where a transmitted signal may arrive at the receiver over multiple transmission paths with extremely long delay spread. A hybrid domain equalizer was proposed in [1] to deal with channels with long delay spread.. The multipath distortion in the received ATSC signal is first tentatively compensated with a frequency domain equalizer on a block-by-block basis. However, inter-block interference (IBI) and intra-carrier interference (ICI) still exist due to the lack of cyclic structure in the received ATSC signal. A time domain interference cancellation algorithm was proposed to cancel the IBI and ICI, based on the tentative decisions in time domain. These two steps are iterated until desired receiver performance is achieved. In this paper, design and implementation of a frequency-time domain equalizer for ATSC system is investigated. The limitation of the previous equalizer design is investigated. An overlapping technique is proposed to improve the performance of frequency domain equalizer. The proposed equalizer and the subsequent design are verified through numerical simulations.