Using phase correction to improve the decision-directed frequency tracking algorithm for OFDM systems

In this paper, we first analyze a kind of decision-directed frequency tracking algorithm for Orthogonal Frequency Division Multiplexing (OFDM) systems, discuss the decision error due to the phase rotation caused by frequency offset, then we propose an improved algorithm based on phase rotation correction. The phase rotation correction procedure is simple and the computational complexity is low. More accurate and stable estimate result can be gotten by use the new algorithm. In most cases, the frequency offset can be estimated and compensated within one OFDM symbol. This results in a shortened convergence time.