非协作通信调制制式识别技术研究

发布时间：2019-03-17 12:07

【摘要】：信号的调制制式识别是非协作通信系统中接收机的关键技术之一。在军事领域中的电子对抗、民事用途中的频谱监测管理都有着重要的应用价值。现阶段的研究方法中,利用小波变换进行制式识别,大多应用于高斯信道条件下,而实际的复杂通信环境中,应针对多径信道下进行制式识别;应用高阶累积量的方法进行制式识别,不足之处在于该方法需要对信号的先验信息进行估计,估计产生的误差影响了识别性能。本文针对上述问题进行了深入研究,主要工作内容如下:改进了小波-高阶循环累积量相结合的方法,第一步:对2ASK、BPSK、QPSK、16QAM信号进行小波变换,然后进行高阶循环累积量变换;第二步:直接对2ASK、BPSK、QPSK、16QAM信号进行高阶循环累积量变换;将第一步与第二步的比值作为特征参数完成了在低信噪比条件下,四种调制制式的分类。该方法即弥补了小波变换仅受限于高斯信道条件下的不足,又解决了高阶累积量方法由于对先验参数进行估计而产生误差影响识别效率的问题。仿真结果表明,在多径衰落条件下,在信噪比为-5dB时,该方法能够较好的识别2ASK、BPSK、QPSK和16QAM信号的调制方式;当多径数目不同时,在信噪比为0dB时,识别率达到90%以上。
[Abstract]:Signal modulation recognition is one of the key technologies of receiver in non-cooperative communication system. Electronic countermeasure in military field and spectrum monitoring management in civil use have important application value. In the current research methods, most of them are used in Gao Si channel, but in the actual complex communication environment, system recognition should be carried out in multi-path channel. It is necessary to estimate the prior information of the signal by using the method of high-order cumulant to identify the system. The error of the estimation affects the recognition performance. The main contents of this paper are as follows: the method of combining wavelet with high order cyclic cumulant is improved. The first step is to transform 2ASK, BPSK, QPSK and 16QAM signals by wavelet transform. Then high-order cyclic cumulant transformation is carried out. In the second step, 2ASK, BPSK, QPSK and 16QAM signals are directly transformed into high-order cyclic cumulants, and the ratio of the first step to the second step is used as the characteristic parameter to classify the four modulation schemes under the condition of low signal-to-noise ratio (SNR). This method not only makes up for the disadvantage that wavelet transform is limited only under Gao Si channel condition, but also solves the problem that high-order cumulant method affects the recognition efficiency because of the estimation of prior parameters. The simulation results show that when the signal-to-noise ratio is-5dB, the modulation mode of 2ASK, BPSK, QPSK and 16QAM signals can be well recognized in multipath fading, and when the number of multipath is different, the recognition rate is more than 90% when the signal-to-noise ratio is 0dB.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.3

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