Enhancing deep-sea communication via time-reversal equalization in reliable acoustic path channels

Area of Science:

• Oceanography
• Acoustic communication
• Signal processing

Background:

• Reliable acoustic path (RAP) channels enable long-range underwater communication.
• Deep-sea environments suffer from strong multipath interference, degrading signal quality.
• Scattering at interface inhomogeneities creates reverberation tails in acoustic signals.

Purpose of the Study:

• To develop and evaluate a method for mitigating multipath interference in deep-sea acoustic communication over RAP channels.
• To improve the reliability and throughput of underwater acoustic networks.

Main Methods:

• Measurements in the South China Sea to characterize RAP channel structures.
• Development of a RAP-adaptive time-reversal equalizer using physics-guided statistical fitting.
• Modeling the channel impulse response as a superposition of multipaths and reverberation.
• Performance evaluation using frequency-hopping spread spectrum M-ary frequency-shift keying and direct-sequence spread spectrum M-ary phase-shift keying.
• Network-level throughput analysis.

Main Results:

• Stable arrival structures and distinct multipath branches were observed across different source depths.
• The RAP-adaptive time-reversal equalizer effectively suppressed multipath interference.
• Reduced inter-symbol interference was demonstrated through experimental validation.
• Improved link reliability was achieved in deep-sea acoustic communication experiments.

Conclusions:

• The RAP-adaptive time-reversal equalizer is a practical physical-layer solution for enhancing deep-sea acoustic networks.
• This method offers a viable approach to overcome multipath limitations in underwater acoustic communication.
• The findings contribute to the advancement of robust long-range underwater communication systems.