Time-Frequency Synchronization Design of OFDM Systems Based on CAZAC Sequence

This paper proposes a new synchronization preamble based on constant amplitude zero autocorrelation (CAZAC) sequence. The weighted symmetry of the sequences and the good autocorrelation of the CAZAC sequences are used to estimate the timing synchronization and frequency offset. In the time domain, two identical weighted sequences are used to get the coarse fractional frequency offset, and then the redundant cyclic prefixes are used to get the fine fractional frequency offset. Finally, it analyzes the effect of integer frequency offset on the sequence, and the integer frequency offset estimation is completed according to the cyclic shift of the sequence. By comparing the proposed method with other methods, it is concluded that the proposed method has better performance of symbol timing estimation and frequency deviation estimation. The proposed method can effectively improve the timing accuracy and frequency deviation estimation accuracy.