关键词: 正交频分复用, 同步, 恒包络零自相关序列, 多径衰落信道

Abstract: In this paper, a novel preamble structure based on weighted CAZAC （Constant Amplitude Zero Auto Correlation） sequence is designed to solve timing ambiguity and high interference peak. The conjugate symmetry of training sequence is used for symbol timing and frequency offset estimation. Then with the redundancy of the cyclic prefix, the fine fractional frequency offset is completed. Finally, the cyclic shifting operation in time domain is adopted to estimate the integer frequency offset. Analysis and computer simulation results show that the proposed method achieves high timing and frequency offset estimation accuracy compared with other algorithm, and solves the problem of synchronization inaccuracy under multipath fading channel. The proposed method has important significance for improving the performance of OFDM system under multipath fading channel environment.

Key words: Orthogonal Frequency Division Multiplexing（OFDM）, synchronization, Constant Amplitude Zero Auto Correlation（CAZAC） sequence, multipath fading channels