Time Domain Feedback Equalizer for Fast Fading Channel in OFDM with Scattered Pilot
In this letter a new feedback equalization scheme to sup press inter earner interference (ICI) in an OFDM system using scattered pilot is investigated On a fast fading channel severe ICI occurs due to a Doppler shift and It deteriorates a bit error rate (BER) seriously because of small subcarrier spacing In an ISDB T receiver the equalization is mainly processed in a frequency domain because the scattered pilot is transmitted over the subcarriers However the frequency domain equalization may not suppress severe ICI in the case of the fast fading channel with a large Doppler shift The proposed equalization scheme uses the scattered pilot symbols transformed in a time domain as the reference signal for feedback taps Numerical results through computer simulation show that the pro posed scheme improves the BER performance especially with low carrier to noise ratio (CNR) conditions
feedback equalizer ofdm ici doppler shift isdb t scattered pilot