A new carrier frequency loop for OFDM systems

In this paper we derive a decision-directed carrier frequency estimator for OFDM systems. The estimator has a closed loop structure and is based on ma ximum likelihood inspired methods. A simplified version of the loop is also developed that can be implemented with relatively low complexity and accep table degradations compared with the optimum scheme. Estimation accuracy is assessed by computer simulation for AWGN and frequency-selective multipath channels. Comparisons are made with other schemes discussed in the literat ure. Simulation results indicate that the proposed loop has better performa nce.