Bistable stochastic resonance enhanced 4-ary PAM signal detection under low SNR

To boost the performance of 4-ary pulse amplitude modulated (PAM) at low signal-to-noise ratio (SNR), bistable stochastic resonance (BSR) system is introduced into digital communications system and get a reliable signal detection scheme. In this paper, we first analyse BSR system for different amplitudes of 4-ary PAM signals. The steady-state of the bistable system will be statistically distinct, and the feasibility of the proposed detection scheme is confirmed. On this basis, we present a detailed study on steady-state transitions of the BSR system, and an explicit expression of the bistable system parameters is derived. By setting the bistable system parameters, bistable system, 4-ary PAM signal, and noise reach the resonance state, and the BSR-based detection scheme is implemented. Moreover, we derive an analytical expression to calculate the symbol error rate (SER) of 4-ary PAM signals with the BSR-based detection under additive white Gaussian noise (AWGN). Finally, the simulation results validate that BSR-based detection scheme can improve the detection performance while efficiently reducing the symbol error rate.