Underwater Wi-Fi

By Cory Nealon

The 25-foot motorboat bobbed gently in Lake Erie, south of downtown Buffalo. It was early afternoon on a warm September day. Only gulls and sailboats interrupted the sun-filled horizon.

But this was no pleasure cruise. It was the start of a potentially paradigm-shifting science experiment. Aboard the vessel were UB doctoral candidates Hovannes Kulhandjian and Zahed Hossain, and their adviser, Tommaso Melodia, associate professor of electrical engineering. The team was dropping 40-pound sensors into the lake to test how the devices could communicate with one another using sound waves, which travel through water more efficiently than other modes of communication.

If all goes well, it will be the first step in the creation of an underwater wireless network, a technological advancement that could lead to improvements in everything from tsunami detection to offshore oil and natural gas exploration to the monitoring of pollution in our waters.

“A submerged wireless network will give us an unprecedented ability to collect and analyze data from our oceans in real time,” says Melodia, who’s heading the project. “Making this information available to anyone with a smartphone or computer, especially when a tsunami or other type of disaster occurs, could help save lives.”

Land-based wireless networks use radio waves to transmit information via satellites and antennae. But radio waves work poorly underwater, which is why such agencies as the Navy and the National Oceanic and Atmospheric Administration (NOAA) rely on sonar and other sound wave-based techniques for deep-sea communication.

For example, NOAA uses sound waves to send data from tsunami sensors on the ocean floor to surface buoys. The buoys convert the sound waves into radio waves that travel to a satellite, which then bounces the sound waves back to land-based computers. Many systems worldwide employ this methodology, Melodia says, but sharing data among them is difficult because each system has a different infrastructure.

The framework Melodia is developing would solve this problem. It would transmit data from existing and future underwater sensor networks to laptops, smartphones and other wireless devices in real time, using protocols compatible with those that land-based networks employ. It would be, in other words, a deep-sea Internet.

The initial research is going well. Aboard the motorboat, after submerging two sensors into Lake Erie, Kulhandjian typed a command into a laptop and waited. “This is cool stuff,” he said. “The sensor nodes are trying to find each other.” Seconds later, high-pitched chirps ricocheted off a nearby concrete wall. Melodia smiled. The test had worked.