Analysis And Research Of Phase-shift Keying Signal Based On Cascade Stochastic Resonance System Under Strong Noise Background

In order to solve the problem of low signal quality in coherent demodulation of phase shift keying(PSK)signal in levy noise,a new method based on cascaded bistable stochastic resonance system to receive 2PSK and 2DPSK signals is proposed.Firstly,the combination of 2PSK signal and 2DPSK signal with nonlinear system model is deduced theoretically.Then the simulation model is established by MATLAB software.The output signal of cascaded bistable stochastic resonance system model is compared with that of bistable stochastic resonance system model and traditional model.Through a large number of numerical simulation experiments,it is found that the 2PSK signal and 2DPSK signal demodulated based on cascaded bistable stochastic resonance nonlinear system model under levy noise background improve the signal-to-noise ratio and reduce the bit error rate compared with their respective nonlinear bistable stochastic resonance system model and traditional model,respectively.The results show that: the strong impulsive levy noise is added to the cascaded bistable stochastic resonance system for coherent demodulation of 2PSK signal.When the input signal enters the nonlinear cascaded stochastic resonance system model,the stochastic resonance phenomenon occurs.At this time,the time-domain waveform is approximately periodic signal,which can be highlighted in the noise.The spectrum peak of cascaded bistable stochastic resonance system after coherent demodulation is 1.42 times of that after primary system coherent demodulation,which is 2.87 times of traditional model.It shows that coherent demodulation model of cascaded bistable stochastic resonance system can output useful information of 2PSK signal more accurately in strong noise background.Compared with the traditional model,the SNR of the new method is increased by 19.6db,and the BER is reduced by 4.3%.The coherent demodulation process of 2PSK signal is described more completely by the band-pass filter,multiplier and low-pass filter.The strong impulsive levy noise is added to the cascaded bistable stochastic resonance system for coherent demodulation of 2DPSK signal.The spectrum peak value of coherent demodulation of cascaded bistable stochastic resonance system model is 1.45 times of that after primary system coherent demodulation,and 4.13 times of that of traditional model.It is shown that the coherent demodulation model of cascaded bistable stochastic resonance system can output useful information of 2DPSK signal more accurately in strong noise background.Compared with the traditional model,the SNR of the new method is increased by 25.3db,and the BER is reduced by6.5%.Compared with 2PSK signal,2DPSK signal has higher output SNR and more accurate transmission effect.Through simulation and comparison with traditional methods,it is proved that the cascaded bistable stochastic resonance coherent demodulation method can effectively improve the transmission quality of 2PSK signal and 2DPSK signal,which indicates its potential application value.