Parallel Multi-Channel Bistable Stochastic Resonance Enhancement for High Rank QAM Signal

To reduce the error code rate of the hard decision of Quadrature Amplitude Modulation (QAM) with the low SNR (Signal-to-Noise Ratio), the paper proposes a method to deal with the QAM signal by using bistable stochastic resonance. On one hand, the mapping relationship between QAM constellation points and parallel multi-channel packet with two-state is constructed, which making it suitable to be deal with in stochastic resonance; On the other hand, the channel noise is reduced by using the cascaded feedback bistable stochastic resonance. In order to realize the division of constellation symbols, synchronization self-feedback adjustment scheme is designed. The conclusions of theoretical analysis and simulation results show that the parallel multi-channel bistable stochastic resonance method can effectively reduce the bit error rate. Compared to the traditional direct hard decision method, when the signal to noise ratio is -4dB, the bit error rate of 32QAM is reduced by 58%. And the BER is lower than the three existing phase noise reduction methods with the same received signal quality.