The ML frequency tracking algorithm for OFDM systems based on pilot symbols and decision data

Pilot symbols inserted into OFDM symbols for channel estimation can be used to track the carrier frequency. The main merit of this method is that good performance of frequency tracking can be obtained without additional data. Further analysis for this method is given both in time and frequency domain, the approximate ML estimation result in time domain is derived und analytical estimation result in frequency domain based on the different style likelihood function is given too. Compared with the original estimation method, new algorithm can decrease the computational complexity greatly, and increase the accuracy of the estimate greatly. The algorithm can work effectively even if the signal to noise ratio is very low.