Abstract: An iterative decision feedback frequency domain equalization algorithm for singlecarrier systems over fast timevarying channels was presented, referring to the intercarrier interference (ICI) cancellation schemes of multicarrier systems. The interference induced by fast fading was iteratively cancelled using a tentative estimation of the received signal obtained from linear equalization. The intersymbol interference induced by fast fading was treated as equivalent noise power during frequency domain equalization based on minimum meansquared error (MMSE) criteria. Simulations show that the proposed method using iteration and decisionfeedback can effectively lower the error floor in fast fading environment.