Multi-tap equalization algorithm for the OFDM system based on the fractional Fourier transform

Abstract

Transmission over wireless channels will introduce intersymbol interference (ISI) as well as interchannel (or intercarrier) interference (ICI). To decrease the effects of ICI, this paper proposes a multi-tap equalizer for the OFDM system based on the fractional Fourier transform (FrFT). In this FrFT-OFDM system, traditional Fourier transform is replaced by fractional Fourier transform to modulate and demodulate the data symbols. And the multi-tap equalizer in the fractional Fourier domain has been designed to equalize the received signal and reduce the ICI. Theoretical analysis and numerical simulation results show that the proposed equalizer in optimal fractional Fourier domain can significantly improve the performance of the system as compared to the Fourier domain equalizer.