Carrier Frequency Offset Estimation with Lower Threshold Effect

Carrier frequency offset estimation is an important technique in receiver design of wireless communications. In many applications, sampled single frequency tone is selected as training symbols/sequence for frequency synchronization. Under this assumption, frequency offset estimation can be regarded as the problem of single frequency estimation. In this paper, an approximate maximum likelihood frequency estimator is proposed. This estimator is an efficient one at moderate and high SNR's. When compared with other estimators, the proposed estimator also has lower variance threshold effect and feasibly computational complexity. The proposed estimator is suitable for high carrier frequency offset cases and coarse/fine frequency synchronization applications.