Frequency synchronization and channel estimation for OFDM/OQAM signals transmitted through Rayleigh fading channels

This work addresses the problems of frequency synchronization and channel estimation for OFDM/OQAM systems in Rayleigh fading channel. A two-step preamble based approach using a new frame structure is proposed. The first step is coarse carrier frequency offset (CFO) estimation and the second step is joint fine CFO (FCFO) and channel estimation. We also propose a FCFO estimator under the assumption that the channel frequency response (CFR) is known at the receiver. When CFR is not available at the receiver, then the interference approximation method (IAM) estimator is used to jointly estimate the CFR and FCFO. Moreover, it is shown that, due to the proposed frame structure, the problems of the FCFO and channel estimation in the second step can be seen as a modified channel estimation problem. We derive the Cramer-Rao lower bounds (CRLB) for the FCFO estimator and compare its performance with CRLB.