Symbol rate estimation method and device of stochastic resonance joint wavelet transform under low signal-to-noise ratio

Abstract

The invention belongs to the technical field of digital communication and particularly relates to a stochastic resonance and wavelet transform combined symbol rate estimation method and device under alow signal to noise ratio condition. The method comprises the steps of carrying out digital sampling on sending signals in a channel, thereby obtaining high power sampled signals; shifting spectrum of the high power sampled signals to intermediate frequency, obtaining intermediate frequency signals, and determining bistable stochastic resonance system parameters; and carrying out iterative processing on the intermediate frequency signals through a bistable stochastic resonance system; carrying out wavelet transform on the signals after the iterative processing; and calculating modulus spectrum for the signals after the wavelet transform, and obtaining symbol rate estimation through observation of peak positions. According to the method and the device, influences that an effect is poor anda wavelet scale is difficult to determine when stochastic resonance is employed independently are compensated, the accurate estimation for symbol rates of weak MPSK and MQAM intermediate frequency signals under a low signal to noise ratio is realized. A simulation experiment shows that output peaks are improved to a certain degree, a signal to noise ratio threshold is reduced, and the method andthe device are significant in the symbol rate estimation under the low signal to noise ratio.

Description

technical field [0001] The invention belongs to the technical field of digital communication, and in particular relates to a method and a device for estimating symbol rate of stochastic resonance joint wavelet transform under the condition of low signal-to-noise ratio. Background technique [0002] In a digital communication system, the symbol rate is related to a series of signal processing procedures such as signal demodulation, baseband sequence recovery, and timing time estimation. In non-cooperative communication, it is often necessary to estimate the symbol rate blindly. However, if the signal-to-noise ratio is extremely low, the symbol rate cannot be accurately estimated, and it is difficult to demodulate the signal, which may lead to loss of important information. Therefore, it is of great value to study the problem of symbol rate estimation under low SNR. Stochastic resonance is a phenomenon in which the periodic output of a nonlinear system is enhanced by the join...

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Problems solved by technology

[0003] Aiming at the deficiencies in the prior art, the present invention provides a method and device for estimating the symbol rate of stochastic resonance combined with wavelet transform under the condition of low signal-to-noise ratio, which makes up for the poor effect of using stochastic resonance alone and its tendency to diverge as a nonlinear system. Disadvantages, reduce the influence of the difficulty of determining the optimal scale of wavelet, effectively reduce the estimation error, and realize the accurate estimation of the symbol rate of weak MPSK and MQAM intermediate frequency signals under low signal-to-noise ratio

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