Digital demodulation signal identification method under non-gaussian noise

Abstract

The invention discloses a novel digital demodulation identification method based on generalized fractional fourier transform (GFRFT) and fractional lower Wigner-Ville distribution (FLOWVD). The novel digital demodulation identification method comprises the steps as follows: received signals are sampled firstly, and then complex envelopes of the signals are restored through Hilbert transform; the maximum value of zero center normalization instantaneous amplitude spectrum density for the signals based on the GFRFT is calculated; the maximum value of the FLOWVD amplitude for the signals is calculated and is taken as characteristic quantity; and in addition, a sorter based on a decision tree is adopted, and the signals adopting different demodulation manners can be identified through data processing, threshold setting and comparison decision. Under the non-gaussian Alpha stable distribution noise, the novel digital demodulation identification method achieves the performance that remarkably surpasses the traditional method, and also achieves higher identification rate and favorable robustness.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a digital modulation signal identification method under non-Gaussian Alpha stable distribution noise, which can be used to identify the modulation mode type of the digital modulation signal under Alpha stable distribution noise. Background technique [0002] Digital modulation signal identification is to determine the modulation mode and corresponding parameters of digital signals under the premise of unknown received signal information, so as to provide necessary parameters and information for signal demodulation, so digital modulation identification is very important in military and civilian fields Applications. The traditional digital modulation recognition assumes that the background noise obeys Gaussian distribution in order to analyze and calculate the signal, but in the actual wireless communication system, there are often some non-Gaussian distributed no...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome above-mentioned deficiencies in the prior art, provide a kind of new method of digital modulation recognition under the stable distribution noise of Alpha, to improve the recognition rate of digital modulation signal under the situation of considering roll-off filter and noise characteristic index change

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