Performance Analysis of a Fine frequency Error Estimator for OFDM Transmission

A method for the estimation of fine carrier frequency error in OFDM modems is analysed. It exploits the OFDM system redundancy given by the cyclic extension (or prefix), and is based on a recursive architecture well suited for high data rate operations. The estimator parameter is optimized with respect to the prefix length and the signal to noise ratio. It is shown that usual values for N g (i.e. Ng = 64 with 512 subcarriers) guarantee good performances, also at very low SNR values. A shorter prefix length, such as N g = 48 or 32, would require an higher SNR of about 1,5 dB and 3,5 dB respectively, for maintaining the same estimator performances. Results are also given in presence of a symbol timing inaccuracy, and a low sensibility of the estimator with respect to timing errors is shown.