| This paper presents a blind adaptive decision feedback equalization (DFE) scheme for QAM signals, which uses block processing and is based on the constant modulus algorithm (CMA). A two-phase scheme is proposed in which the equalizer switches from the blind mode to decision feedback mode after the blind scheme has converged. If the error level is low and the equalizer output is reliable then DFE is successful and all intersymbol interference (ISI) can be removed by this scheme. The block DFE scheme is tested with two blind equalization schemes (i)CMA and (ii) CMA+AMA. Their performance is compared with the original CMA/AMA scheme and to each of the blind equalization schemes operating alone. The convergence behavoir of the AMA cost function is used to evaulate the performance of the different schemes. In addition, the average symbol error rate (SER) is compared for the different schemes by Monte Carlo Simulation. |