Study On BER Of Coherent Reception Of 2PSK Signal In Different Noise Background Based On Stochastic Resonance Theory

In this dissertation, For the problem of high bit error rate (BER) of transmission signal in the strong noise background, a new method based on stochastic resonance is proposed in the case where there are only additive noise and additive and multiplicative noise are present, which is used to reduce the bit error rate of binary phase shift keying (2PSK) signal by coherent demodulation receiving. First, the steady-state BER of 2PSK signal in both above mentioned are derived theoretically in the nonlinear system. Then simulink modeling is computed and analyzed in MATLAB. By contrast with the conventional demodulation method, it is found that the BER of 2PSK signal based on stochastic resonance has significantly reduced under low input signal to noise (SNR) circumstances. In particular, the BER curve decreases rapidly when the range of input SNR is from -14.4 dB to -5.2 dB. It can reduce 20.1% when the input SNR equals -7.4 dB. The BER of 2PSK signal through nonlinear system is further discussed by changing the system parameter where additive and multiplicative are existed and noise intensity fixed. Experimental results show that the BER in 2PSK stochastic resonance system excited by both additive and multiplicative noise comparing with the system only with additive noise is reduced by 16.7%. And multiplicative noise makes the system have some robustness. Large amount of simulations show the obvious effects of stochastic resonance method in the low input SNR by contrast with the conventional method, and it predicts some potential applications.