Abstract:In troposcatter communication systems, factors such as clock deviation of the transceiver, random movement of scatterers, and relative movement of the transceiver can cause the carrier frequency offset of the received signal. Traditional frequency offset estimation algorithms need to make a trade-off between estimation accuracy and estimation range, making it difficult to obtain wide range high-precision frequency offset estimation. Additionally, due to the inherent fast fading characteristic of troposcatter channel, the statistical performance of frequency offset estimation algorithms in troposcatter channel will significantly decrease. In order to solve the problems of traditional method, a frequency offset estimation method based on segmented pilot was studied. By dividing the pilot sequence into three segments and inserts them into a data frame, the method uses the head and middle pilots to obtain coarse frequency offset estimation, uses the head and tail pilots to obtain fine frequency offset estimation, and uses the coarse estimation results to phase unwrap the fine estimation results. Simulation results show that this method can obtain wide range high-precision frequency offset estimation. Furthermore, the proposed algorithm is combined with frequency hopping hidden diversity technology. Simulation results demonstrate that the proposed method can achieve a 2~3dB signal-to-noise ratio (SNR) gain in the troposcatter channel under mid-to-high SNR compared with traditional method, meeting the practical application requirements of troposcatter communication systems.
