DSSS系统中基于BFT和FRFT的线性调频干扰抑制  

Linear frequency modulation interference suppressing in DSSS system based on BFT and FRFT

作　　者：许定根[1] 程乃平[2] 周辉[3] 

机构地区：[1]装备指挥技术学院研究生管理大队,北京101416 [2]装备指挥技术学院光电装备系,北京101416 [3]装备指挥技术学院信息装备系,北京101416

出　　处：《通信学报》2010年第S1期137-142,共6页Journal on Communications

基　　金：国家高技术研究发展计划("863"计划)基金资助项目(2006AA701419)~~

摘　　要：分析了双正交Fourier变换(BFT)的运算复杂度,给出了一种快速算法,即利用泰勒级数展开,将离散BFT计算转化为离散距和常系数的乘积。接着,提出了一种DSSS系统中抑制多分量线性调频干扰(LFM)的新方法:利用BFT对接收到DSSS信号进行变换,通过峰值搜索估计出各个LFM分量的调频率,进而得到进行FRFT所需的旋转角度,然后在FRFT域利用级联的滤波器进行干扰抑制。分析和数值仿真结果表明,此方法能有效抑制多分量LFM干扰,与其他时频分析的干扰抑制算法相比,在不损失性能的情况下,运算复杂度明显减小,减少到O(N2)。A fast approach to BFT (bi-orthogonal Fourier transform) was proposed, which transforms BFT to the product of the constants and discrete moments with Taylor series expansion, after the computational complexity of BFT was dis-cussed. A method of multicomponent LFM interference suppression in DSSS was introduced. First the received signal is transformed by BFT, thus the value of every chirp ratio is estimated by peak-searching in the BFT domain,and the corresponding rotational angles of FRFT can be figured out from these values.Then the interference in fractal domain is excised by serial filters. Discussion and numerical simulation results show the validity of this method.In addition,when compared with other two-dimension time-frequency filtering algorithms,it reduces computational complexity with no loss of BER performance.

关 键 词：直接序列扩频 双正交Fourier变换 分数阶FOURIER变换 LFM干扰 

分 类 号：TN914.42[电子电信—通信与信息系统]