Transcript
Slow WiFi is a source of irritation that nearly everyone experiences. Yet, wireless devices in the home consume ever more data, congesting the WiFi network further.
Fortunately, researchers at Eindhoven University of Technology have come up with a surprising solution: a wireless network based on harmless infrared rays. The rated capacity is more than 40 Gbit/s per ray, and there is no need to share, since every device gets its own ray of light.
The system conceived in Eindhoven is simple and, in principle, cheap to set up. The wireless data comes from a few central 'light antennae', mounted on ceilings and other locations, where they are able to very precisely direct the rays of light supplied by an optical fiber.
Since there are no moving parts, the system is maintenance-free and needs no power source. The antennas contain a pair of 'passive diffraction gratings' that radiate light rays of different wavelengths at different angles. Changing the light wavelengths changes the direction of the rays of light. And, since a safe infrared wavelength is used that does not reach the vulnerable retina in your eye, this technique is harmless.
If you walk around as a user and your smartphone or tablet moves out of the line of sight, then another light antenna takes over. The network tracks the precise location of every wireless device using its radio signal transmitted in the return direction. It is a simple matter to add devices: they are assigned different wavelengths by the same light antenna and so do not have to share capacity. Moreover, there is no longer any interference from a neighboring WiFi network.
Current WiFi uses radio signals with a frequency of 2.5 or 5 gigahertz. The system conceived at TU Eindhoven uses infrared light with wavelengths of 1500 nanometers and higher; this light has frequencies that are thousands of times higher, some 200 terahertz, which makes the data capacity of the light rays much larger. In tests, the team achieved a speed of 42.8 Gbit/s over a distance of 2.5 meters. For comparison, the average connection speed in the Netherlands is two thousand times less (at just 17.6 Mbit/s).
And even if you have the very best WiFi system available anywhere in the world, you won't get more than 300 Mbit/s in total, which is 1 percent of the speed per ray of light achieved by the Eindhoven study.
The researchers are still working on the technology that tracks the location of all the wireless devices as well as on the essential central fiber-optic network connecting the light antennas. They expect it will be five years or more before the new technology will be in stores and the first devices to be connected to this new kind of wireless network will be high data consumers devices like video monitors, laptops or tablets.
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