Dr. Aijun Song: Underwater Communications & Research

Decoding the Depths: Dr. Aijun Song and the Frontiers of Underwater Acoustic Communication

To most of humanity, the Earth’s oceans remain a vast, opaque frontier—a realm where radio waves refuse to travel and light is swallowed by the dark within a few hundred meters. For decades, exploring and communicating beneath the waves relied on rudimentary, low-bandwidth tools.

Enter Dr. Aijun Song, an innovator whose research is fundamentally rewriting how we connect with, monitor, and understand aquatic environments. As an Associate Professor in the Department of Electrical and Computer Engineering at the University of Alabama, Dr. Song is pioneering advanced underwater acoustic communications, intelligent surfaces, and autonomous marine robotics, pushing humanity closer to a truly interconnected “Internet of Underwater Things” (IoUT).

Bridging the Wireless Gap Beneath the Waves

While terrestrial technology thrives on high-speed Wi-Fi, 5G, and satellite links, electromagnetic waves attenuate rapidly underwater. Sound, however, travels efficiently through water. This core physical reality forms the foundation of Dr. Song’s work.

Rather than treating underwater acoustics as a simple alternative to radio frequencies, Dr. Song’s research tackles its complex challenges head-on: high propagation delays, severe multipath fading, wind-driven surface noise, and spatial-temporal channel fluctuations. By combining rigorous signal processing, advanced estimation techniques, and cutting-edge machine learning, his team develops robust communication systems that allow data to flow reliably across long distances beneath the sea.

Pioneering Underwater Reconfigurable Intelligent Surfaces (RIS)

One of Dr. Song’s most exciting contributions to marine engineering involves Underwater Acoustic Reconfigurable Intelligent Surfaces (UA-RIS) and multi-layered variants (ML-ARIS).

In terrestrial radio communications, intelligent reflecting surfaces are widely studied to manipulate wireless signals without active power-hungry transmitters. Translating this concept to acoustics was a formidable hurdle due to the unique properties of sound waves and practical constraints on phase control.

Dr. Song and his collaborators have broken new ground by designing prototype UA-RIS architectures capable of passive beamforming. By utilizing specialized piezoelectric materials and adjustable load impedances, these smart surfaces can steer reflected sound waves precisely toward target directions. This innovation effectively:

• Extends communication range without escalating power consumption.
• Boosts data rates for deep-sea exploration.
• Minimizes acoustic interference in surrounding marine ecosystems, creating an environmentally friendly footprint.

Autonomous Systems and Environmental Stewardship

Beyond theoretical signal processing, Dr. Song’s work has deep practical implications for environmental protection and autonomy. His lab frequently collaborates on deploying Autonomous Underwater Vehicles (AUVs) for water-observing technologies, helping agencies monitor water quality, track environmental changes, and map aquatic ecosystems.