Iterative ML-based estimation of carrier frequency offset, channel impulse response and data in OFDM transmissions

This paper provides an approximate closed formsolution to the problem of data-aided joint maximum likelihood estimation of the carrier frequency offset and of the channel impulse response in an Orthogonal Frequency Division Multiplexingtransmission over a multipath fading channel. Thisresults in a novel pilot-aided feedforward estimator, that can be employed for pilot-based receiver training. It is also shown how the novel joint estimation strategy can be exploited in an iterative (turbo) receiver structure to track the fast channel andfrequency offset changes occurring during the transmission of infomation symbols. The performance of this structure is assessed by computer simulations and is compared with that provided by other estimation/detection strategies.