基于双谱频率估计的快跳频捕获方法  

A method for FFH synchronous capture based on bispectrual frequency estimation

作　　者：刘攀 王伟 朱红 

机构地区：[1]空间电子信息技术研究院,陕西西安710100

出　　处：《电子设计工程》2015年第17期101-104,共4页Electronic Design Engineering

摘　　要：针对现有快跳频(Fast-Frequency Hopping,FFH)通信同步捕获所需跳数多的问题,提出了一种基于双谱频率估计(Bispectrual Frequency Estimation,BFE)的捕获方法。该方法通过重构解跳信号,计算重构信号的双谱(三阶自相关函数的傅里叶变换)来估计当前跳信号所使用的频点,确定其在跳频序列中的位置,从而在数跳之内完成跳频捕获。相对于FFT进行频率估计,BFE算法利用双谱进行频率估计可以有效抑制高斯白噪声的影响。该算法通过频率搜索,迅速找到当前跳信号所使用的跳频频点在跳频序列中的位置,与传统方法相比缩短捕获时间。仿真结果表明,BFE算法在信噪比(SNR,signal-to-noise ratio)为4 d B时,九跳之内即可实现100%捕获,且虚警概率仅为3.16E-5。To settle the common disadvantage-high consumption of hops caused by existing FFH synchronous capture method, a method based on bispectrual frequency estimation （BPF） was proposed. By reconstructing the de-hopped signal and computing the bispectrum （the Fourier transformation of the third-order correlation function） of the reconstructed signal, this method obtained the frequency occupied by current hop and located its position in the frequency sequence directly. Then synchronous capture would be finished in few hops. Bispectrum analysis outperformed the direct FFT analysis in frequency estimation through suppressing the impact of additive Gaussian white noise efficiently. BFE attained the frequency information about the current received hop in the frequency sequence much more quickly than the conventional technique did through frequency estimation. This shortened the coarse acquisition time tremendously. It is shown that when SNR is 4dB, by using BFE, coarse acquisition probability fetches 100 percent in 9 hops with false alarming as low as 3.16E-5.

关 键 词：快跳频 同步 捕获 双谱频率估计 

分 类 号：TN914.4[电子电信—通信与信息系统]