Orthogonal Chirp Division Multiplexing for Underwater Acoustic Communication

Area of Science:

• Underwater Acoustic Communication (UWAC)
• Signal Processing
• Wireless Communication

Background:

• Underwater acoustic channels suffer from multipath propagation and frequency fading.
• Traditional Orthogonal Frequency Division Multiplexing (OFDM) faces challenges in these environments.
• Exploiting channel diversity is crucial for reliable UWAC.

Purpose of the Study:

• To investigate a novel UWAC system using Orthogonal Chirp Division Multiplexing (OCDM).
• To evaluate OCDM's performance against OFDM in UWAC scenarios.
• To demonstrate OCDM's robustness against frequency fading.

Main Methods:

• Developed an OCDM system utilizing modulated chirp signals derived from the Fresnel transform.
• Implemented the OCDM system for UWAC applications.
• Conducted performance evaluations in an experimental water tank and a replayed underwater channel.

Main Results:

• OCDM demonstrated robustness against frequency fading, particularly in underloaded scenarios.
• Performance comparisons showed advantages of OCDM over traditional OFDM.
• Experimental results validated the effectiveness of OCDM in UWAC.

Conclusions:

• OCDM is a promising technique for enhancing UWAC system reliability.
• The use of chirp signals effectively exploits multipath diversity.
• OCDM offers a viable alternative to OFDM for challenging underwater communication.