提出了一种完整的OFDM时频联合载波频偏估计方案。首先利用时域插入的CAZAC前导码进行符号粗同步和时域小数频偏估计,然后使用频域插入的连续导频对FFT解调后的数据进行整数频偏估计,最后使用相邻符号的连续导频对残余的相位误差进行跟踪,得到精确的载波频率同步。给出了算法各部分的FPGA实现框图和硬件电路实测效果。仿真结果表明,本方案可以对±N/2个子载波间隔内的载波频偏实施快速捕获与跟踪,估计精度达到10-3~10-4,具有很好的工程实用性。
This paper proposed a complete carrier frequency offset estimation scheme of jointing time and frequency for OFDMsystems. First, it estimated the symbol coarse synchronization and the time domain decimal frequency offset estimation by usingCAZAC preamble inserted in time domain. Then, used the continuous pilot inserted in frequency domain to estimate the integerfrequency offset. And last, used continuous pilot of adjacent symbols to track the residual phase error to get the precise carrierfrequency synchronization. And it gave the FPGA implementations of various parts of the algorithm and hardware circuit meas-ured result. The simulation results show that the scheme can rapidly capture and track carrier frequency offset in ±N/2 sub-cartier interval. The scheme's estimation aceuracy is at 10-3~10-4 ,with good engineering practicability.