Fast High-Precision Doppler Frequency Offset and Rate Joint Estimation

Addressing the carrier synchronization challenges in high-dynamic low-speed satellite communications, a novel joint estimation algorithm for carrier Doppler frequency offset and rate of change based on FFT is proposed. The fundamental concept involves utilizing discretely inserted pilot signals, initially reducing the Doppler rate of change to frequency offset through conjugate differential operation. Subsequently, a frequency-domain algorithm is applied to estimate the Doppler rate of change. Based on the estimated rate of change, the data is then corrected, and the corrected data is utilized to estimate the frequency offset. Simulation results indicate that the performance of this algorithm closely approaches the Modified Cramér-Rao Bound (MCRB), and it exhibits a low operating threshold. When estimating with 128 symbols, the carrier parameters can be accurately estimated under 0 dB signal-to-noise ratio (SNR) conditions. Furthermore, computational complexity analysis reveals that the algorithm has relatively low complexity, making it suitable for hardware implementation and capable of satisfying the requirements of low-speed service communications under extremely low SNR conditions.