Sustained underwater acoustic communications with environmental-based time-reversal

Area of Science:

• Underwater Acoustic Communication
• Signal Processing
• Numerical Modeling

Background:

• Time-reversal is crucial for underwater communication, relying on channel replicas for matched filtering and alignment.
• Traditional channel replicas are susceptible to noise and distortion from environmental variability.
• Accurate channel state information is vital for reliable underwater acoustic communication.

Purpose of the Study:

• To propose an alternative to traditional time-reversal methods in underwater acoustic communication.
• To replace noisy, distorted channel replicas with noise-free, time-updated replicas generated by a numerical model.
• To improve the performance of underwater communication systems by mitigating channel variability effects.

Main Methods:

• Utilized a numerical model constrained by previously identified environmental parameters to generate updated channel replicas.
• Replaced traditional, noisy channel replicas with model-generated, noise-free replicas.
• Applied the proposed method to real-world data from a shallow water environment.

Main Results:

• The proposed method demonstrated a mean square error gain of up to 5.4 dB compared to traditional time-reversal.
• Unsupervised analysis confirmed the effectiveness of the noise-free replica generation.
• Successful transmission of a quadrature phase shift key modulated signal at 25.6 kHz carrier and 4 kbit/s over 900m.

Conclusions:

• The numerical model-based approach offers a significant improvement over traditional time-reversal in underwater acoustic communication.
• Noise-free, time-updated channel replicas enhance signal processing and reduce communication errors.
• This method provides a robust solution for underwater communication in dynamic environments.