Communication signal modulating and identifying method based on generalized S transformation

Abstract

The invention provides a communication signal modulating and identifying method based on generalized S transformation. The communication signal modulating and identifying method comprises the following steps of: (1) carrying out analytic signal configuration on an input modulating signal according to the characteristic of an input signal to noise ratio modulating signal to obtain an analytic signal to be used as a signal for carrying out generalized S transformation; (2) configuring a Gaussian window function needed by the generalized S transformation; (3) determining a Gaussian window width factor sigma according to an expression formula of the generalized S transformation; carrying out the generalized S transformation on an input modulation signal by combining short-time Fourier transformation and the Gaussian window function to obtain time-frequency energy distribution images of the modulation signal; and (4) comparing energy images of all modulation signals according to the time-frequency energy distribution images obtained by the step (3) to find out a difference between the time-frequency energy distribution images of all modulation signals which are subjected to the generalized S transformation; selecting a frequency strip quantity with concentrated energy, a maximum value ratio of high-frequency component energy to low-frequency component energy, energy time domain distribution, high-frequency and low-frequency component extreme value time domain distribution and high-frequency component extreme value distribution so as to identify all modulation signals. According to the invention, a high identification rate is achieved under the condition of a low signal to noise ratio, and the method is suitable for modulating and identifying communication signals under a heavy clutter environment.

Description

technical field [0001] The invention belongs to the field of communication signal modulation identification and relates to a communication signal modulation identification method based on generalized S transform. technical background [0002] The basic task of communication signal modulation identification is to determine the modulation mode and other signal parameters of the received signal under the condition of multi-signal environment and noise interference, so as to provide a basis for further analysis and processing of the signal. Communication signal identification technology can automatically identify the modulation mode of communication signals. It is an important technical basis for general-purpose receivers and smart modems based on software radio. It also has very important applications in multi-system communication interconnection and software radio. [0003] Using the time-frequency joint distribution of the signal to describe the energy distribution characteri...

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Problems solved by technology

[0004] In recent years, the method of non-stationary signal analysis based on generalized S transform has been applied in the fields of seismic signal processing, medical signal processing and electric power technology, but the field of communication signal modulation recognition is still in its infancy, and there is no relatively mature use of generalized S transform The method of modulation identification appears. The generalized S transform combines the characteristics of the current mainstream short-time Fourier and wavelet transform, and makes up for some defects of these two methods. Therefore, it has great advantages in the identification of communication signal modulation in complex electromagnetic environments. big potential

[0005] But at present, there is no literature report on the communication signal modulation recognition method based on the generalized S transform at home and abroad.

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