扩谱通信中的自适应窄带干扰抑制算法研究

发布时间：2018-04-05 12:08

  本文选题：扩谱通信　切入点：窄带干扰抑制　出处：《国防科学技术大学》2014年硕士论文

【摘要】：扩谱通信是目前广泛运用的一种抗干扰通信体制,为了提高系统抗干扰能力,往往在接收端进行窄带干扰抑制处理。论文研究了频域窄带抑制基本原理和基于前向连续均值去除(FCME)双门限干扰抑制算法,针对FCME算法迭代耗时、不能适用宽信噪比范围等缺陷,提出了一种改进的自适应频域三门限干扰抑制算法,仿真表明改进算法能够适应更大信噪比范围。最后利用FPGA实现了改进算法,并在实际工程中得到应用。论文以重叠加窗FFT干扰抑制算法为基本方法,首先阐述了加窗选择、FFT、IFFT、干扰检测、干扰抑制等子模块原理。针对干扰检测方法,论文研究了单门限算法、双门限算法和FCME算法,编程仿真了FCME干扰抑制算法性能,分析发现该算法在大信噪比时,导致信号严重损失,无法适应接收信号信噪比大动态范围情况。为了解决上述问题,论文提出了三门限自适应窄带干扰抑制算法,算法基于系统干扰容限、干信带宽比等先验参数,设计了高、中、低三个门限实现干扰检测与抑制,仿真表明算法能够自适应处理强弱信噪比输入。最后利用FPGA实现了自适应三门限干扰抑制算法,并仿真分析了算法实际性能与资源消耗。
[Abstract]:Spread spectrum communication is a widely used anti-interference communication system. In order to improve the anti-jamming ability of the system, narrowband interference suppression is often carried out at the receiving end.In this paper, the basic principle of narrow-band suppression in frequency domain and the dual-threshold interference suppression algorithm based on forward continuous mean method are studied. Due to the time-consuming iteration of FCME algorithm, it can not be used in wide signal-to-noise ratio (SNR) range.An improved adaptive three-threshold interference suppression algorithm in frequency domain is proposed. The simulation results show that the improved algorithm can adapt to a larger SNR range.Finally, the improved algorithm is realized by using FPGA, and it is applied in practical engineering.In this paper, the basic method of overlapped windowed FFT interference suppression algorithm is introduced. Firstly, the principle of windowed selected FFT IFFTFT module, interference detection and interference suppression module is described.In this paper, single threshold algorithm, double threshold algorithm and FCME algorithm are studied, and the performance of FCME interference suppression algorithm is simulated. It is found that the algorithm leads to serious loss of signal when the signal to noise ratio is large.It can not adapt to the large dynamic range of SNR of received signal.In order to solve the above problems, a three-threshold adaptive narrowband interference suppression algorithm is proposed. Based on the prior parameters such as system interference tolerance and ratio of signal to bandwidth, three thresholds are designed to detect and suppress interference, such as high, medium and low thresholds.Simulation results show that the algorithm can deal with strong and weak SNR input adaptively.Finally, the adaptive three-threshold interference suppression algorithm is implemented by using FPGA, and the actual performance and resource consumption of the algorithm are simulated and analyzed.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN914.42
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本文编号：1714697