Joint Carrier Frequency Offset, Sampling Time Offset and Channel Estimation for OFDM-OQAM Systems

Among the alternative multicarrier modulation techniques to orthogonal frequency division multiplexing (OFDM), a derivative of OFDM based on offset quadrature amplitude modulation (OFDM-OQAM) has been one of the most prominent to alleviate the sensitivity problem of the former to timing and frequency mismatch. In this paper, we propose an improved joint estimation method for carrier frequency offset (CFO), sampling time offset (STO) and channel impulse response (CIR) in OFDM-OQAM systems. The proposed method instruments a data-aided maximum-likelihood (ML) joint estimation of the unknown parameters, as derived under an assumption of Gaussian noise and independent input symbols by splitting the interference into pilot, non-pilot and noise terms. Performance evaluation is carried out through simulations by comparing the proposed method with a highly-cited previous work which considers all the three types of parameters in one development. The improvements in the results indicate the superiority of the proposed joint ML-based estimator.