An Improved Joint Time and Frequency Offset Estimation for OFDM Systems in Multipath Fading Channel

An improved method of joint time and frequency offset estimation is proposed in this paper. In the scheme, two neighboring identical pilot symbols are embedded in the frequency domain. Zadoff-Chu sequence is utilized as the pilot symbols for its advantage of ideal autocorrelation property. To overcome the Multipath Fading effect, a new timing metric using the length of CP is applied to ensure that the resultant FFT starting point is located in the middle of the ISI-free CP part. The simulation shows that the proposed method has the better performance than the conventional OFDM symbol timing estimation method in the multipath fading channel especially for the case when the first path isn't the strongest. Moreover, it can achieve the reliable and robust fractional frequency offset estimation.