Parallel Concatenated Frequency-Domain Decision-Feedback Equalization Scheme

A turbo-type scheme that uses parallel concatenation and turbo block decision feedback equalization (TBDFE) is proposed to suppress linear intersymbol interference. Two design methods are investigated based on the minimum mean square error (MMSE) criterion. In the first algorithm, the hard-decision data output from one detector are used as input of the feedback filter in the other detector. In the second algorithm, the feedback filter is directly designed from soft-decision data made by the coordinate detector. From performance evaluations we observed that the TBDFE can significantly outperform existing iterative block DFE (IBDFE) whether on a dispersive static channel or on a Rayleigh fading channel. Moreover, both the two design methods do not increase the computational complexity.