Fast burst synchronisation technique for OFDM-WLAN systems

An MMSE (minimum mean square error) based joint timing and frequency synchronisation algorithm utilising a simplified frame structure is proposed for fast burst synchronisation in orthogonal frequency division multiplexing (OFDM) systems. A single synchronisation symbol is exploited in the time domain to give, first, an estimate of coarse frame starting position and fine frequency offset, and later, in the frequency domain, the multiple of subcarrier spacing frequency offset using a reference symbol power adjustment (RPA) technique. The power of the start symbol, which also acts as a reference symbol in differential modulation, is varied linearly to determine the multiple subcarrier frequency offset. The performance of the proposed frame is confirmed by simulation for a differential quaternary phase shift keying (DQPSK) system in a multipath fading environment