DIVING NEWS
Underwater Internet a step closer
Picture: KAUST, Xavier Pita.
Can’t even wait to get back to the surface to share your latest underwater photos or videos? Scientists in Saudi Arabia believe they have found a way to provide scuba divers with a sub-aquatic Internet service.
Recreational divers might not feel the need, but for those working under water the Aqua-Fi system could provide a welcome breakthrough.
It uses light beams in the form of LEDs or lasers to transmit data instantly, allowing multimedia messages to be shared in real time. It would also allow divers to communicate between themselves under water without the limitations of hand-signals or conventional comms systems.
At present radio can be used to transmit data under water but only over short distances, while acoustic signals are longer-distance but have a limited data rate. Visible-light communications overcome these distance and volume limitations – but depend on a clear line of sight between transmitter and receiver.
Associate Professor Basem Shihada and his team at King Abdullah University of Science & Technology (KAUST) have built an Aqua-Fi prototype.
It has been tested by simultaneously uploading and downloading multimedia between two computers a few metres apart in static water. They recorded a maximum data transfer speed of 2.11 megabytes per second and an average delay of 1.00 millisecond for a round trip.
In practice Aqua-Fi would use radio waves to send data from a diver’s smartphone to a small “gateway” computer attached to their kit. Photos and videos are converted into a series of 1s and 0s, which are translated into light beams turning on and off at very high speed.
16 June 2020
A light-detector connected to the receiving topside computer, linked to the Internet conventionally by satellite, senses the variation and converts the binary code back into the original footage.
Low-energy LEDs would be used for transmission over short distances, and more power-hungry lasers for longer-distance communication.
“This is the first time anyone has used the Internet under water completely wirelessly,” says Prof Shihada. “We have created a relatively cheap and flexible way to connect underwater environments to the global Internet.”
Now the researchers are working to improve the link quality and transmission range by using faster electronic components.
They are looking to use a spherical receiver that can capture light from all angles, to overcome the difficulty of keeping a light beam perfectly aligned with the receiver in moving waters.
“We hope that one day Aqua-Fi will be as widely used under water as wi-fi is above water,” says Prof Shilada.
