Blind Symbol Synchronization for OFDM Systems Using Cyclic Prefix in Time-Variant and Long-Echo Fading Channels

In this paper, blind symbol synchronization for orthogonal frequency-division multiplexing (OFDM) systems based on the cyclic prefix (CP), considering time-variant long-echo fading channels, is introduced. The basic idea of our contribution is to obtain an estimate of channel-tap powers using the correlation characteristics of the CP. The maximum-likelihood (ML) estimation of the correlation characteristics is derived and employed for channel-tap power estimation. An intersymbol-interference (ISI) metric is minimized using the estimate of channel-tap powers. The metric, which is based on the statistical properties of received samples, turns the mobility factor into a coefficient, which can be simply compensated. The metric is suitable for both short- and long-echo channels. The performance is analyzed. The proposed algorithm has moderate complexity. Simulations confirm the advantages of the proposed estimator.