Joint Maximum Likelihood Estimation of Carrier and Sampling Frequency Offsets for OFDM Systems

In orthogonal frequency-division multiplexing (OFDM) systems, carrier and sampling frequency offsets (CFO and SFO, respectively) can destroy the orthogonality of the sub-carriers and degrade the system performance. In this paper, we propose a new joint CFO and SFO maximum-likelihood (ML) estimation scheme extending Moose's CFO estimation scheme using two long training symbols in the frequency-domain (FD). In particular, we derive FD Cramer-Rao bounds (CRBs) for the mean square errors (MSEs) of the CFO and SFO estimation. Simulation results show that the proposed ML scheme exhibits better performance than the other existing methods.