A Joint Frequency Offset Estimation Algorithm for 5 G NTN

The integration of satellite communication systems with terrestrial 5G networks, aimed at establishing a comprehensive and seamless air-space-ground integrated network that caters to the diverse service requirements of users, represents a significant direction for the future of communications. However, low-orbit satellite high-dynamic communications links face various challenges, such as low SNR and large frequency offsets. This paper proposes a joint subcarrier frequency offset (CFO) estimation algorithm for the 5G(fifth-generation mobile communication technology) Non-Terrestrial Networks (NTN) scenario, integrating 5G and low Earth orbit (LEO) satellite communication systems. The algorithm uses a combination of Fast Fourier Transform (FFT) and interpolation for initial coarse frequency offset estimation, followed by phase-based fine estimation using Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS). The simulations demonstrate that the proposed methodology achieves comprehensive coverage of the Doppler frequency shift range with enhanced precision. It exhibits robust performance in conditions characterized by low signal-to-noise ratio (SNR) and large frequency offsets, thereby significantly enhancing the overall system's capabilities.