基于连续符号平均功率方差最小化的CM-OFDM系统盲载波频偏估计算法

摘要

Aiming at the problem that the digital signal is sensitive to the Carrier Frequency Offset (CFO) in the Orthogonal Frequency Division Multiplexing (OFDM) system,a blind carrier frequency offset estimation algorithm (CM-OFDM) based on continuous symbol mean power variance minimization for Constant Modulus-OFDM (CM-OFDM) systems is put forward.The algorithm constructs the cost function in views of the constant modulus of the frequency domain signal,compensates the time domain signal in the CM-OFDM system by testing three frequency offset estimators,and finally estimates the CFO using the Monte Carlo method.In addition,the algorithm uses the forward and inverse transform of Fast Fourier Transform (FFT) to form a unitary matrix,thus the computational complexity of the algorithm will be reduced.Simulation results show that the proposed algorithm can effectively improve the performance of CFO estimation and has good robustness.%针对数字信号在正交频分复用(OFDM)系统中传输受载波频率偏移(CFO)敏感的问题,提出一种基于连续符号平均功率方差最小化的恒模OFDM(CM-OFDM)系统盲载波频偏估计算法.该算法基于频域信号恒模特性构造出代价函数,通过试验三个频偏估计量对CM-OFDM系统中的时域信号进行补偿,并最终采用蒙特卡罗的方法估计出CFO.此外,利用快速傅里叶变换(FFT)的正反变换构成一个酉矩阵,从而降低算法计算过程的复杂度.仿真表明,提出的算法有效的提高了CFO估计的性能,并且具有较好的鲁棒性.