FBMC-OQAM信号子载波盲估计

为了解决滤波器组多载波(filter-bank multi-carrier,FBMC)信号的子载波参数盲估计问题,提出一种基于四阶累积量的方法来估计FBMC-OQAM信号子载波参数。首先,截获交错正交幅度调制(offset quadrature amplitude modulation,OQAM)的FBMC信号并检测信号频谱来确定循环频率的范围;然后,分析循环频率与四阶累积量的代数关系;最后,得出四阶累积量的峰值受原型滤波器影响且仅在其循环频率等于子载波频率处存在。通过检测四阶累积量峰值的位置和个数能有效估计子载波频率和数目。仿真表明,当信噪比大于2 dB时,算法对FBMC-OQAM信号的子载波参数盲估计正确概率为98%。

FBMC-OQAM Signal Subcarrier Blind Estimation

To address the problem of blind estimation of subcarrier parameters of filter-bank multi-carrier signals, a method for estimating subcarrier parameters of FBMC-OQAM signals based on fourth-order cumulants is proposed. Firstly, the FBMC signal of the offset quadrature amplitude modulation is intercepted, and its spectrum is used to determine the range of the cyclic frequency. Then, the algebraic relationship between the cyclic frequency and the fourth-order cumulants is analyzed. Finally, because the value of the fourth-order cumulants’ peak is affected by the prototype filter and only exists when the cyclic frequency equals to the subcarrier frequency, the subcarrier frequency and number of FBMC signals can be estimated by detecting the locations and number of fourth-order cumulants’ peaks. Simulation results show that when the SNR is greater than 2 dB, the correct probability of blind estimation of the subcarrier parameters of the FBMC-OQAM signal is 98%.