An Improved FFT channel interpolation in OFDM systems

Abstract:

An Edged Extend Fast Fourier Transform (EFFT) channel interpolation algorithm is proposed. The presented EFFT algorithm can extend linear mirror pilots nearby the edge of the effective frequency band of each OFDM (Orthogonal Frequency Divided Multiplexing) symbol and the performance of channel estimation is enhanced by the added mirror pilots. The simulation results show that the performance of the EFFT channel interpolation algorithm is similar to that of Wiener filter channel estimation algorithm under the condition of low SNR and modulation mode, while there was about 1dB improvement when compared to traditional FFT channel interpolation algorithm. The complexity of the EFFT channel interpolation was similar to that of traditional FFT channel interpolation algorithm and there is a significant reduction of calculations when compared to Wiener filter channel estimation algorithm. Moreover, the EFFT channel interpolation is suitable for the existing standards and has no influence on the transmission efficiencies.

Key words:Orthogonal Frequency Divided Multiplexing; channel interpolation; Fast Fourier Transform; Edged Extension