基于小波变换的密集测距仪脉冲干扰抑制技术研究

发布时间：2018-04-27 16:14

本文选题：L波段数字航空通信系统1 + 正交频分复用　；参考：《中国民航大学》2014年硕士论文

【摘要】：L波段数字航空通信系统1(L-DACS1)是未来L波段数字航空通信系统的一个候选方案,采用频分双工(FDD)与正交频分复用(OFDM)技术。由于L波段的频谱资源稀缺,L-DACS1系统以内嵌的方式工作在L波段测距仪(DME)系统频道间。因此OFDM接收机不可避免的会受到DME信号的强烈干扰。为了抑制DME脉冲干扰,本文提出了基于小波变换的L-DACS1机载接收机方案。首先,根据L-DACS1系统协议规范,介绍了L-DACS1的系统参数和工作原理。其次,给出了测距仪的工作原理和信号模型。在典型的干扰场景下,详细分析了DME对L-DACS1机载接收机的干扰影响。然后,介绍了测距仪脉冲干扰抑制常规方法,脉冲熄灭算法和脉冲限幅算法,并仿真验证了常规方法对L-DACS1系统比特误码率(BER)性能的影响。最后,本文提出了基于小波变换的测距仪脉冲干扰抑制方法,采用小波变换去噪方法重构测距仪脉冲信号,然后通过时域脉冲干扰消除抑制测距仪脉冲干扰。计算机仿真结果显示:在高斯白噪声信道环境下和多径信道环境下,本文提出的接收机方案可显著提高链路传输可靠性。
[Abstract]:L-band digital aeronautical communication system (1LDACS1) is a candidate scheme for the future L-band digital aviation communication system. It adopts the technology of frequency division duplex (FDD) and orthogonal frequency division multiplexing (OFDM). The L-DACS1 system works in an embedded manner between the channels of the L-band rangefinder DME-system due to the scarcity of spectrum resources in the L-band. Therefore, the OFDM receiver will inevitably be strongly interfered with by the DME signal. In order to suppress DME pulse interference, a scheme of L-DACS1 airborne receiver based on wavelet transform is proposed in this paper. Firstly, according to the L-DACS1 system protocol specification, the system parameters and working principle of L-DACS1 are introduced. Secondly, the working principle and signal model of the range finder are given. In the typical jamming scene, the influence of DME on L-DACS1 airborne receiver is analyzed in detail. Then, the conventional pulse interference suppression method, pulse quenching algorithm and pulse limiting algorithm for rangefinder are introduced, and the effect of conventional methods on bit error rate (BER) performance of L-DACS1 system is verified by simulation. Finally, this paper presents a method of the range finder pulse interference suppression based on wavelet transform. Wavelet transform denoising method is used to reconstruct the range finder pulse signal, and then the time domain pulse interference is eliminated to suppress the range finder pulse interference. Computer simulation results show that the proposed receiver can significantly improve the reliability of link transmission under Gao Si white noise channel environment and multipath channel environment.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：V243.1;TN972

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