A Novel Synchronization Scheme for OFDM Over Fading Channels

This paper presents a novel preamble-based synchronization scheme for orthogonal frequency division multiplexing systems over time-variant multipath fading channels. A new timing metric is derived with the use of a local synchronizing sequence (LSS). We propose one specifically designed training sequence which consists of two segments of equal length where each segment is constructed from a different pseudo-noise (PN) sequence. The advantages of using the LSS are twofold: multipath effects are reduced in the new timing metric and the metric trajectory is impulse-like. The new algorithm is shown to provide excellent performance in timing estimation even in severe time-variant fading channels. As for frequency synchronization, a two-step approach handles both fractional and integer frequency offset providing a large frequency acquisition range without loss of estimation accuracy