Blind OFDM carrier frequency offset estimation in the presence of DC Offset

The estimation of carrier frequency offset (CFO) and DC offset is a crucial issue in an OFDM direct-conversion receiver. Recently, a blind CFO estimator based on the correlation of the received OFDM samples has been proposed. In this paper, this symbol-wise CFO estimator is extended to consider the presence of DC offset. Assuming a constant DC offset during one OFDM symbol period, we can roughly estimate the DC offset by averaging the whole symbol, and then removing it to perform the CFO estimation. Also, by rewriting the signals in matrix forms, we propose a new cost function which can be used to estimate the CFO free of DC offset. The validity of the proposed estimators is confirmed by simulations.