Finally, the Underwater Wireless Modem We’ve All Been Waiting For

October 16, 2013 - via University at Buffalo

You can use the internet in Antarctica. You can tweet from the International Space Station. And wireless internet blankets much of the globe. But go underwater and it’s pretty hard to find TCP/IP. Until now, that is. Welcome to the Internet of Things, undersea edition.

Researchers at the University at Buffalo have floated their first wireless internet modems, designed for underwater use. They’re gigantic, slow, and noisy, but they could be a step toward making undersea sensors cheaper and easier to hook up to the rest of the world.

On a warm fall afternoon last month, the Buffalo researchers chartered a 25-foot yacht, sailed out into Buffalo’s Small Harbor and dropped three of the yellow 40-pound acoustic modems into the placid waters of Lake Erie.
The Teledyne Benthos modems, which resemble oversized tinker toy components, talk underwater using a high-pitched chirping sound, which can be easily picked up at about 1 kilometer’s range.

Typically they use their own networking protocols, but funded by a National Science Foundation grant, the University at Buffalo team has plugged them into a Gumstix Linux board and reprogrammed the modem to speak an aquatic version of TCP/IP — the networking protocol that all devices on the Internet use to communicate with each other.

“This means that you can take an underwater network and make it accessible through the internet,” says Tommaso Melodia, the professor at the University at Buffalo who is leading the research effort. He sees these networked underwater sensors doing everything from monitoring for tsunamis to scouting for submarines to helping with deep sea exploration.

But these networks are very, very slow. In fact, that’s why Melodia and his team had to rewrite TCP/IP. On dry land, we can use high frequency radio waves to transmit our internet data at near-light speeds. They’re fast, high-bandwidth and inaudible. But radio doesn’t do so well underwater. There you need acoustic networking. It’s slow, low bandwidth and audible to both humans and sea creatures.

Photo: Douglas Levere/University at Buffalo
So the University at Buffalo researchers had to get their modems to work even when there is a very long wait time as packets are chirped underwater from modem to modem.

“You go pretty much at the same data rates that you would be able to achieve with a modem in the ’80s; it’s a few kilobits per second at most, and often less than that,” says Melodia. That’s not enough to broadcast a video stream from the deep seas, but if you want to hack together a deep sea sensor that could tweet out a Tsunami warning, it would do just fine.

In the future, Melodia wants to develop a high frequency version of the modem, which would be less likely to affect marine life. “Underwater and acoustic networking are still in their infancy, and are evolving,” he says, adding, “much of our ongoing research in this field is trying to lay the basis for faster, more reliable, and secure… networks.”
Melodia and his team will present a paper on their research, titled “The Internet Underwater: An IP-compatible Protocol Stack for Commercial Undersea Modems,” at an underwater networking conference in Taiwan next month.

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Author:Robert McMillian