基于循环平稳理论的宽带航空数据链系统信号检测与估计研究

发布时间：2019-04-02 09:22

【摘要】：L频段宽带航空数据链系统1(L-DACS1)是民航未来航空移动通信系统的主要技术手段。为解决民航甚高频通信中频率资源匮乏的问题,L-DACS1以内嵌方式工作于测距仪(DME)频道之间,而DME脉冲信号对L-DACS1正交频分复用(OFDM)接收机产生的干扰将显著恶化宽带航空数据传输链路的性能。针对这一问题,论文开展基于循环平稳理论的宽带航空数据链系统OFDM接收机DME干扰检测与估计的研究。主要内容如下:首先,简单介绍L-DACS1相关物理层参数以及前向传输链路传输模型,给出DME脉冲信号模型,仿真结果表明DME脉冲干扰对L-DACS1链路传输性能产生很大影响。其次,按照循环统计量相关理论,给出循环平稳信号的判定依据、循环自相关函数以及循环谱密度的数学描述,并针对调幅信号的循环谱进行仿真验证。在此基础上,理论证明OFDM信号及载波偏置DME信号具有循环平稳特性,详细推导给出载波偏置DME信号循环谱数学表达式。仿真结果显示,OFDM信号与DME信号的循环谱在各自特定循环频率处有峰值,验证了理论分析的正确性。再次,基于OFDM信号及载波偏置DME信号循环谱的差异,完成对L-DACS1系统OFDM接收机中载波偏置DME信号的检测,并利用高斯脉冲对的强相关特性实现载波偏置DME信号在时域接收序列中的定位。最后,在判定存在DME干扰信号的条件下,提出利用载波偏置DME信号循环谱峰值估计其平均功率的方法,并仿真验证该方法的准确性。仿真结果表明,本文提出的方法能有效检测出L-DACS1系统OFDM接收机中的DME干扰信号,并准确估计出其平均功率。
[Abstract]:The L-band broadband air data-link system 1 (L-DACS1) is the main technical means of the aviation mobile communication system in the future. In order to solve the problem of the lack of frequency resources in the high-frequency communication of the civil aviation, the L-DACS1 is embedded within the range finder (DME) channel, and the interference of the DME pulse signal to the L-DACS1 orthogonal frequency division multiplexing (OFDM) receiver will significantly degrade the performance of the broadband air data transmission link. In this paper, the research on the detection and estimation of the DME interference of the OFDM receiver based on the cycle-stationary theory is carried out. The main contents are as follows: First, the physical layer parameters of L-DACS1 and the forward transmission link transmission model are briefly introduced, and the DME pulse signal model is given. The simulation results show that the DME pulse interference has a great effect on the transmission performance of the L-DACS1 link. Secondly, according to the theory of cycle statistics, the decision basis of the circular stationary signal, the mathematical description of the circulation self-correlation function and the density of the cyclic spectrum are given, and the cyclic spectrum of the amplitude-modulated signal is simulated and verified. On this basis, the theory proves that the OFDM signal and the carrier bias DME signal have the loop-stationary characteristics, and the mathematical expression of the cyclic spectrum of the carrier bias DME signal is derived in detail. The simulation results show that the cyclic spectrum of the OFDM signal and the DME signal has a peak at the specific cycle frequency, and the correctness of the theoretical analysis is verified. Thirdly, based on the difference of the cyclic spectrum of the OFDM signal and the carrier bias DME signal, the detection of the carrier bias DME signal in the OFDM receiver of the L-DACS1 system is completed, and the positioning of the carrier bias DME signal in the time domain receiving sequence is realized by using the strong correlation characteristic of the Gaussian pulse pair. And finally, in the condition that a DME interference signal is judged, a method for estimating the average power of the DME signal cycle spectrum peak by using a carrier wave is proposed, and the accuracy of the method is simulated. The simulation results show that the method proposed in this paper can effectively detect the DME interference signal in the OFDM receiver of the L-DACS1 system, and estimate the average power accurately.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V243.1

【相似文献】