Adaptive stochastic resonance aided demodulation for the challenge of deepwater extremely vertical acoustic communication

In this paper, we propose a binary frequency shift keying (2FSK) demodulation method via adaptive frequency scaling stochastic resonance (AFS-SR), aiming to improve reliability of deepwater extremely vertical acoustic communication. Through the sea trial experiment, we prove the greatest problem of vertical acoustic channel is the significantly amplitude fading of the signal. And the amplitude fading of the signal is more severe, when the underwater acoustic is transmitted from negative gradient to positive gradient. For verifying the reliability performance of the proposed approach, a simulated comparison with traditional 2FSK coherent and non-coherent demodulation is conducted. And computer simulation results indicate that, the method proposed exhibits better bit error rate (BER) performance than traditional methods in low signal-to-noise ratio (SNR). Moreover, for the BER value of 10^-3, the method we proposed provides approximately 11dB better BER performance than traditional demodulation. The result demonstrates that the proposed method has a good application prospect in vertical acoustic channel. Therefore, it is extremely helpful to develop the level of riser safety monitoring for deepwater drilling riser.