An Optimum Decision Feedback Equalizer for SC-FDMA Systems

In this paper, we propose an optimum decision feedback equalizer (DFE) scheme for single carrier frequency division multiple access (SC-FDMA) systems. The scheme is composed of a frequency domain linear equalizer (FD-LE) and a time domain DFE which is made up of a feedforward filter and a feedback filter. The feedforward linear filter is a noise whitening filter (NWF) which whitens the spectrum of the noise colored by the FD-LE. Since the spectrum of the noise is white at the input of the decision device, decision is optimum. Simulation results show that the bit error rate performance of the proposed method is superior to the FD-LE and the conventional DFE, particularly at low signal to noise power ratio.