Coarse frequency offset estimation using a delayed auto-quadricorrelator in OFDM-based WLANs

This paper presents a frequency offset estimation scheme using a delayed auto-quadricorrelation method which takes advantage of the symmetric property of a short training preamble in OFDM-based WLANs. Based on the discovered symmetries between real and imaginary values in the short training preamble, we present an effective frequency offset estimation scheme which widens the estimation range to one quarter the sampling frequency (0.25f_s =5MHz) in an ideal condition and up to ten times the subcarrier spacing (10xf_sub = 3125 KHz) in WLAN under the noisy environment.