Robust Time-Domain Fine Symbol Synchronization for OFDM-Based Packet Transmission Using CAZAC Preamble

We propose an OFDM-based fine symbol synchronization scheme with robust threshold setting. Our proposed scheme applies a constant-amplitude zero auto-correlation (CAZAC) preamble with two identical halves, and implements the fine symbol timing in the time-domain (TD). By utilizing the proposed CAZAC preamble, the cross-correlation between received vector and the known preamble can generate a flat region on the left-hand side of the main-lobe, which provides a high resolution for fine symbol timing. Moreover, we analyze the downsides of the estimation range for threshold calculation in the Awoseyila´s scheme, and then improve the threshold setting by employing an estimation range with robustness. The conducted simulation results show that our proposed scheme without signal-to-noise ratio (SNR) estimation has significant improvement as compared to the Awoseyila´s scheme in high SNR region, and has asymptotical timing performance as compared to the Wang´s scheme which requires the knowledge of SNR for optimal threshold setting.