Abstract：To solve the poor performance of traditional blind orthogonal frequency division multiplexing(OFDM) oversampling rate estimation method at low signal to noise ratio(SNR) and multipath channel conditions, a novel blind OFDM oversampling rate estimation method was proposed based on the spectrum characteristics of OFDM baseband sampling signals. The improved moving covariance method was adopted to estimate the carrier frequency, and to establish the power spectrum of received signal by Welch method. An optimal cosine rolloff filter was designed with an optimal rolloff factor to make the cutoff frequency of the designed filter approach that of sampling signal. The oversampling rate was estimated based on the spectrum characteristics of oversampling signals to realize blind estimation for different OFDM signals oversampling rate. The simulation results show that the mean square error(MSE) of OFDM signals oversampling rate is less than 0.2 at the conditions of -2 dB SNR and multipath channel. The proposed method has good estimation performance at the conditions of low SNR and multipath channel without any prior knowledge.
2012, Vol. 33 
