一种基于改进FFT的MPSK载波估计方法

针对多进制相移链控(MPSK)信号相干解调中载波同步问题,提出一种基于Zoom FFT及频域内插的方法进行载波提取。该方法通过信号的非线性变换,在时频域内实现载波频率的粗估计,在此基础上通过频域内的插值校正实现载波的准确提取。仿真试验结果表明,本算法提取的载波具有较高的准确性,估计的最大相对误差只有10-6量级。该方法不需要特定图案的前导字,结构简单,可估计的载波频率适应范围大,在高信噪比的情况下硬件实现系统实时性好。

A QPSK Carrier Estimation Method Based on Improved FFT

Aiming at the carrier synchronization problem in MPSK coherent modulation,a new algorithm based on Zoom FFT and frequency intervene is proposed for carrier estimation MPSK transmission.The carrier is estimated approximately in time-frequency domain through nonlinear transformation and Zoom FFT,then it is distilled exactly by intervene in frequency domain.The simulation result shows that the carrier estimated with this method is more precise,and the maximal relative estimation variance is only 10-6.A special preamble is not necessary and wide range carriers can be estimated by this method.It can also be implemented easily on a digital hardware platform under high SNR condition.