Automatic identification method of conventional digital signal modulation mode having no need of a priori knowledge

Abstract

The invention belongs to the communication technique area related to the method for automatic recognizing the general used digital signal modulation modes without need of prior knowledge. First, the noise is separated out through the A1 parameter. Then the CW signal is recognized. The signal is preprocessed so as to separate the analog signal or unknown signal with no constant envelope. The Cp in the normalized parameter of instantaneous frequency distinguishes the frequency-modulated signal and the phase-modulated signal. The frequency-modulated signal are sorted by the peak number Nf in the normalized parameter. The phase-modulated signals are sorted through the square spectrum and fourth power spectrum. The emulation of BPSK, QPSK, OQPSK, pi / 4QPSK, MAK, FSK, FM, CW indicates that the recognition rate reaches 95%.

Description

technical field [0001] The invention belongs to the technical field of communication, in particular to an automatic identification method for common digital signal modulation modes. Background technique [0002] Signal automatic modulation recognition technology has high practical value. In terms of civilian use, in order to implement effective radio spectrum management, relevant authorities often need to monitor the transmission of civilian signals in order to maintain control over them or to discover and monitor unregistered transmitters; at this time, signal authentication, interference identification, etc. all involve modulation automatic identification. In terms of military and national security, modulation automatic identification technology is more widely used. In order to obtain communications intelligence, the communication intelligence system of any country must first clarify the modulation method of the signal, and then implement correct demodulation and subsequ...

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Problems solved by technology

[0022] 1. The algorithm of this method depends on prior knowledge, such as the exact carrier frequency, carrier phase, baud rate, symbol synchronization and signal sampling rate and the signal symbol are integer multiples of the signal; but these parameters are difficult in actual situations obtained, or can only be estimated to obtain poor accuracy values, the errors of these parameters have a great influence on the signal characteristics and its judgment

[0023] 2. Focuses on theoretical research, does not consider the influence of the modulation parameters of the actual modulation signal, so the mathematical model itself has a large error, and the feasibility is not good

[0024] 3. This method and many other documents can identify that the types of signal modulation are limited, and it is required to receive signals in the scope of its discussion. When the unknown signal is a modulation method in this range, it can be identified, but when the unknown signal is not in the scope of discussion When the modulation method is used, it will misjudge

[0025] 4. There is no effective separation of noise, which is very important, because in the actual communication signal recognition, the separation of noise is the first step. If it is not separated, the automation of recognition cannot be realized

[0026] 5. The most used QPSK, OQPSK and pi / 4QPSK signals are not classified, but simply divided into one category

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