Comments on "Class of Cyclic-Based Estimators for Frequency-Offset Estimation of OFDM Systems"

This comment corrects several errors found in the paper, "Class of Cyclic-Based Estimators for Frequency-Offset Estimation of OFDM Systems". In addition, we show that the minimum variance unbiased estimator for frequency offset derived in the above paper is the maximum-likelihood estimator when the timing delay is perfectly known.