Radio waves travel with difficulty through water , making it difficult for divers or submersibles to transmit information wirelessly to the surface.
However, scientists are trying to change that by developing an underwater version of Wi-Fi. The research is described in a study recently published in the journal IEEE Communications .
This new experimental system, known as Aqua-Fi, basically works when the diver starts sending data (photos or videos) from his smartphone (contained in an airtight casing). The data is transmitted as radio waves to a device mounted in the diver’s air tanks .
Then a microcomputer would convert the data into a series of ultra-fast pulses of light, each pulse representing a 1 or 0 in binary code. Those pulses would then be emitted towards the surface, using an integrated 520 nanometer laser or an array of green LEDs : LEDs could send the data relatively short distances with little power, while the laser could send it further but would use more energy to do it.
Upon reaching the surface, the light pulses would be received by a photodetector on the underside of a ship, and a computer would process the data. From there, the files could be uploaded to the Internet via satellite .
Until now, the Aqua-Fi system has been used to upload and download multimedia between two computers located a few meters apart in calm waters. However, before it can come into use in the real world, it will have to adapt to meet challenges such as the scattering effect of light from water.