An improved frequency offset tracking algorithm for OFDM systems based on pilots

In OFDM systems different symbols are impacted differently by the channels which change fast. In this paper, a frequency offset tracking algorithm based on pilots which are transmitted for channel estimation in OFDM systems is proposed in time-varying multi-path channel. We analyse the algorithms based on pilots combined with decision data in frequency domain and derive an improved approximate Maximum Likelihood Estimation (MLE). The simulation results show that the improved algorithm whose computational complexity is not high in the time-varying multi-path channel can increase the accuracy of the frequency offset tracking.