High-speed noncoherent underwater acoustic communication using permutation alphabets and sliding hypothesis-tree...

Area of Science:

• Electrical Engineering
• Signal Processing
• Underwater Communications

Background:

• Underwater acoustic (UWA) channels present significant challenges for reliable communication due to time-Doppler shifts and multipath propagation.
• Existing communication systems often struggle with joint synchronization and decoding in these adverse conditions.

Purpose of the Study:

• To introduce a novel framework, sliding hypothesis-tree decoding (SHDT), for joint synchronization and decoding in UWA communication.
• To demonstrate the effectiveness of SHDT in constructing robust noncoherent communication links.

Main Methods:

• Developed SHDT framework for joint synchronization and decoding.
• Constructed a noncoherent link using Polar coding and super permutation frequency shift keying.
• Evaluated the link performance using replay simulations on benchmark UWA channels (Watermark, Baltic Sea) with randomized time-Doppler shifts.
• Tested the link in a high-mobility shallow-water horizontal channel.

Main Results:

• Achieved spectral efficiency of 0.149-0.222 bit/s/Hz.
• Demonstrated a low frame error rate across seven diverse UWA channels.
• Confirmed successful synchronization and decoder performance comparable to simulations in a real-world adverse channel.
• Showcased SHDT's ability to decouple performance limitations from synchronization to information decoding.

Conclusions:

• SHDT provides a robust solution for joint synchronization and decoding in challenging UWA environments.
• The framework enables reliable communication, even in non-line-of-sight and high-mobility scenarios.
• SHDT is particularly suitable for lower-rate communication methods requiring dependable data transfer.