HTS systems use multibeam technology to overlap service area coverage and multiple frequency multiplexing to increase satellite link capacity. Gateway stations are closely integrated with user beam clusters for efficient, two-hop communication via shared satellite resources, allowing spatial isolation and frequency re-use.
Beam hopping allows satellites to flexibly allocate capacity as business requirements shift. Synchronizing the satellite's beam hopping payload with ground signals is crucial to ensure the user terminal receives uninterrupted service.
The review details three key aspects of beam hopping in HTS systems: precise satellite-ground synchronization, burst-mode signal demodulation, and dynamic resource allocation. The synchronization between ground service signals and the timing of satellite beam switches is critical for consistent reception.
A signaling-assisted synchronization method is proposed for satellite-ground hopping beam alignment. Ground gateway stations send an auxiliary synchronization signal in burst mode. The on-board controller matches this signal and triggers beam switching, achieving accurate synchronization. The method uses a pseudo-random capture sequence and RM(7,64) encoding in line with DVB-S2X standards to maintain robust performance at low signal-to-noise ratios.
The demodulation process involves frequency conversion, serial-to-parallel data handling, demodulation, and peak time correlation detection. Precise time reference points are set using these correlation peaks, followed by Reed-Muller decoding to extract beam control information.
A guide frequency assistance method is also introduced for high-precision timing deviation estimation. The approach uses BPSK-modulated sequences and a four-sample point estimation algorithm to measure timing deviation. Simulations show estimation accuracy exceeds 98 percent under normal operational conditions and remains stable with frequency bias up to +/-10 percent.
The proposed algorithm increases synchronization accuracy while reducing complexity compared to traditional digital filter methods, delivering improved timing performance and system efficiency for satellite beam hopping communications.
Research Report: A Fast and High-Precision Satellite-Ground Synchronization Technology in Satellite Beam Hopping Communication
Related Links
Institute of Space Radio Technology, Beijing Institute of Technology
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