A robust timing and frequency synchronization algorithm for HF MIMO OFDM systems

A time-frequency synchronization method using shift-orthogonal constant amplitude zero auto correlation (CAZAC) sequences constructing the synchronization preamble is designed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) shortwave systems. The timing synchronization and integral frequency offset is accomplished by using the good correlation properties of training sequence. The simulations results show that the new algorithm works well at low SNR over HF channel. Finally, it provides higher timing synchronization accuracy even in distributed MIMO-OFDM systems with different time offsets.