Robust orbital-angular-momentum-based underwater acoustic communication with dynamic modal decomposition method

Area of Science:

• Acoustic communication
• Underwater acoustics
• Signal processing

Background:

• Acoustic communication using orbital angular momentum (OAM) offers efficient data transmission in aquatic environments.
• Current methods for detecting OAM topological charge (TC) require full azimuthal acoustic pressure measurements, reducing efficiency and increasing bit error rate (BER).

Purpose of the Study:

• To propose and validate a modified dynamic modal decomposition (DMD) method for precise TC detection in OAM acoustic beams.
• To address the limitations of conventional methods by enabling TC detection from partially sampled acoustic fields.

Main Methods:

• A modified dynamic modal decomposition (DMD) approach is developed for TC detection.
• The method utilizes partial sampling of the acoustic field, reducing measurement requirements.
• Numerical simulations are employed to validate the accuracy and performance of the proposed method.

Main Results:

• The modified DMD method accurately extracts single or multiple TC magnitudes from partially sampled acoustic fields.
• The proposed scheme demonstrates a lower BER compared to conventional orthogonal decoding under identical noise interference.
• The modified DMD approach shows increased robustness against array misalignment.

Conclusions:

• This research presents an efficient demodulation solution for acoustic OAM communication.
• The modified DMD method simplifies receiver array design and enhances long-distance underwater data transmission capabilities.