Block DFE and windowing for Doppler-affected OFDM systems

Recently, a minimum mean-squared error (MMSE) block linear equalizer based on a band LDL/sup H/ factorization has been proposed for equalization of orthogonal frequency-division multiplexing (OFDM) systems affected by Doppler spread. In this paper, we extend this approach towards two directions. First, we design an MMSE block decision-feedback equalizer (DFE) based on the band LDL/sup H/ factorization. Both performance and complexity are analyzed. Second, we enhance the performance of the linear equalizer by means of receiver windows tailored to the band LDL/sup H/ factorization approach. Simulation results show that the proposed techniques are effective in reducing the error floor caused by the intercarrier interference (ICI).