Frequency offset insensitive demodulation algorithm for satellite‐based automatic identification system

AbstractSummaryThe frequency offset caused by the Doppler shift and the oscillators instability degrades the performance of satellite‐based demodulators for automatic identification system (AIS) signals unless proper synchronization algorithms are used. A noncoherent demodulation algorithm (NDA) based on cyclic redundancy check (CRC) error correction is proposed in this paper, which is able to tolerate large frequency offsets, thus avoiding the use of an explicit frequency synchronizer. To reduce the complexity, the number of CRC register states for error correction can be limited. Simulation results of the proposed algorithm are presented and compared with other demodulation algorithms in the literature in terms of bit error rate (BER) and packet error rate (PER).We proposed a noncoherent demodulation algorithm based on cyclic redundancy check (CRC) error correction, which is able to tolerate large frequency offsets, thus avoiding the use of an explicit frequency synchronizer. To reduce the computational complexity, the number of CRC register states for error correction has been limited. Simulation results prove that the proposed demodulation algorithm outperforms that of other AIS demodulation algorithms in the literature. View Figure