Joint C F O and SF O Estimator for O FD M Receiver Using C ommon Reference F requency
Abstract: In this paper, we propose a maximum likelihood method for jointly estimating carrier frequency offset (CFO) and sampling frequency offset (SFO) in receivers for orthogonal frequency division multiplexing signals. The proposed estimator exploits the fact that a single source (such as a crystal oscillator or voltage controlled oscillator) is typically used in modern wireless receivers to provide a reference frequency for both the sampling clock and the radio frequency synthesizers. The proposed CFO es&mator is capable of a large CFO es&ma&on range (i.e., more than half of intercarrier spacing) without extending the length of the training sequence. The Crรกmer-Rao lower bound (CRLB) of the variance of the estimated joint CFO and SFO is derived and compared to the CRLBs of the CFO and SFO estimators in the literature. More importantly, the proposed method is validated on a real-time wirelesstest bed.