Frequency Offset Estimation and Compensation Using Superimposed Training

We propose in this paper some methods to estimate and compensate for the harmful carrier frequency offset that could be present in pass-band wireless communications. Although there are efficient methods to estimate the frequency offset when training sequences are employed, our method exploits instead the presence of an implicit/superimposed training sequence. Implicit training schemes have been proposed before for the channel estimation task but they all assume a data communication link free of any frequency offset and they all fail in the case when this offset exists. It is therefore mandatory to estimate and compensate for this offset before proceeding to use the channel estimation methods already available in the open literature as a previous step for the ultimate goal of data recovery.