A T/4 fractionally spaced predictive decision feedback  blind equalization algorithm

In order to eliminate the severe inter-symbol interference caused by severe channel fading, this paper presents a T/4 fractionally spaced predictive decision feedback equalizer based on modified Dual Mode Multi-modulus Algorithm (DM-MMA). The forward and feedback filters are designed separately with modified DM-MMA. The forward filter is designed to be a T/4 fractionally spaced filter, such that the taps are spaced at a fraction of the symbol rate, while the feedback filter with a predictive structure is implemented as a symbol rate filter. According to the simulation experiment results under the condition of two severe fading channels, the equalizer presented in this paper can avoid ill-convergence solution caused by conventional decision feedback structure, and the steady-state mean-square errors of the equalizer are less than that of the T/4 fractionally spaced equalizer based on Constant Modulus Algorithm(CMA), T/4 fractionally spaced decision feedback equalizer based on CMA, and T/4 fractionally spaced predictive decision feedback equalizer based on Modified DM-MMA, which makes it more suitable for QAM signals.