Decoding the Deep: Dr. Aijun Song and the Frontier of Underwater Wireless Communications

When we think about modern wireless communication, our minds naturally drift to the airwaves above us—5G towers, satellite internet, and Wi-Fi networks connecting our daily lives. Yet, over 70% of our planet remains covered by water, a vast and largely opaque realm where traditional radio frequency waves simply cannot survive.

Enter Dr. Aijun Song, an innovator whose research is rewriting how we explore, 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 groundbreaking advancements in underwater acoustics, robotics, and signal processing that are helping bridge the digital divide beneath the sea.

The Challenge of the Blue Frontier

Communicating underwater is notoriously difficult. Because electromagnetic radio waves attenuate rapidly in water, GPS and standard wireless protocols become entirely useless beneath the surface. Instead, scientists rely on acoustic waves—sound waves—to transmit data.

However, acoustic communication comes with its own severe bottlenecks:

• Glacial Speeds: Sound travels roughly 1,500 meters per second in water—fast to human ears, but drastically slower than light-speed radio waves, leading to heavy propagation delays.
• Multipath Interference: Sound waves bounce endlessly off the surface, the ocean floor, and underwater structures, creating echoes and distorted signals.
• Harsh Dynamics: Wind-driven surface waves, currents, and shifting temperatures constantly alter the underwater channel, making reliable data transmission a moving target.

For decades, these obstacles hindered humanity’s ability to build a true “Internet of Underwater Things” (IoUT). Dr. Song’s work tackles these exact friction points head-on.

Pioneering Underwater Acoustic Reconfigurable Intelligent Surfaces (UA-RIS)

One of Dr. Song’s most notable contributions involves the development of Underwater Acoustic Reconfigurable Intelligent Surfaces (UA-RIS) and multilayered acoustic reflecting architectures.

Traditional underwater modems require heavy power to push signals across long distances. Dr. Song’s research introduces smart surfaces embedded with specialized materials (such as piezoelectric layers) whose load impedances can be dynamically adjusted. By utilizing passive beamforming and in-phase/quadrature (IQ) modulation through these surfaces, acoustic waves can be precisely steered and amplified toward specific targets without requiring massive energy outputs.

This technology effectively extends communication ranges, boosts data rates, and minimizes acoustic noise pollution—crucial for protecting marine life while enabling high-speed underwater networking.

From Theory to the Riverbank: Robotics and Education

Dr. Song’s research does not live solely inside theoretical simulation papers or laboratory tanks. Alongside his student research team, he has routinely taken cutting-edge marine robotics and autonomous underwater vehicles (AUVs) out into the field—conducting real-world demonstrations in locations like the Black Warrior River and Lake Tuscaloosa. These systems act as next-generation water-observing nodes, capturing environmental health data vital for ecological conservation and resource management.