Carrier Synchronization Method Based on Bit-level Superimposed Training Sequence

‍ ‍‍ ‍For the problems of large carrier frequency offset and limited bandwidth resources in burst communication， a scheme based on bit-level superimposed training sequence is proposed. At the transmitter， the sparse coding codewords is superimposed on the training sequence by modulo-2 bit-by-bit， so that the training sequence is implied in the transmitted data and they share spectrum resources during transmission. And the superposition scheme can enhance the anti-interception ability of burst communication. At the receiver， a carrier synchronization method with strong anti-interference ability is proposed. The method uses the hidden training sequence to complete the carrier frequency recovery， and the coarse frequency estimation and the fine frequency estimation are combined to improve the estimation accuracy. The simulation results show that the scheme has a frequency offset capture range of $\pm \mathrm{0.45}$. Compared with the synchronization scheme based on time-division multiplexing （TDM） system， the synchronization proposed scheme can estimate frequency offset more accurately at low signal-to-noise ratio （SNR） （-4 dB）， and has a gain of 0.5 dB and 0.7 dB in AWGN channel and Rayleigh fading channel respectively.