A frequency-domain decision feedback equalizer for multipath echo cancellation

A block decision feedback equalizer (DFE) implemented in the frequency domain is derived. The new algorithm is directly applicable to multipath echo cancellation in digital transmission systems. The new equalizer consists of two distinct parts, namely a filtering part of low complexity implementable on a single VLSI chip, and an efficient filter updating part which can be implemented in today's technology DSPs. In both parts, block formulations in the frequency domain are developed, with different block sizes for each case. The resulting equalizer enjoys the computational advantages of frequency domain implementations (studied extensively for linear equalization schemes) offering at the same time the well-known superior performance of DFE.