Wi-Fi works by sending information via radio waves, but systems that rely on light – be it infrared or visible – have the potential to achieve much faster speeds. A system proposed by a team at Eindhoven University of Technology (TU/e) uses infrared rays beamed down from antennas in the ceiling and is claimed to be capable of data transfer rates of over 40 Gbps, regardless of how many devices are hooking into the network.
Beaming radio waves of either 2.5 GHz or 5 GHz, regular Wi-Fi can reach transfer speeds of about 300 Mbps at most, but the average is far lower than that. Even so, that's more than fast enough to serve a few devices on a local network, but frustrating slow-downs are increasingly common, as more family members connect their phones tablets and computers to the home network, and houses continue to fill up with connected TVs, fridges, lights, robots, heating systems and home assistants.
On the other hand, a system sometimes called "Li-Fi" uses light waves to transmit information, either through the visible light or infrared spectra. Light-based transmission systems can either help take the load off traditional Wi-Fi or potentially replace it, since it won't slow down as more devices jump in. Speeds can reach as high as 10 Gbps, and are reportedly more secure than Wi-Fi since line-of-sight is needed between the device and the transmitter.
The system developed at TU/e is built around light antennas, which the team says could be mounted on the ceiling to beam an internet connection throughout a room. The signal would be sent to the antennas by way of an optical fiber, and from there it passes through a pair of "passive diffraction gratings," whose job is to transmit different wavelengths of light at different angles.
Using an array of these antennas means that even if line of sight is lost between a user's device and one antenna, another will be there to pick up the slack without the user noticing the jump. The system would know when to make these switches by tracking the radio signals transmitted by the device to the antenna, which are also used to upload data back to the internet. According to the team, the system requires no power and very little maintenance.
With frequencies as high as 200 THz, the system has apparently been clocked transmitting data at speeds of up to 42.8 Gbps as far as 2.5 m (8.2 ft) and remaining completely safe for human health. Even better, since each antenna will designate each device its own wavelength, nobody else's Netflix binges will drag down your speeds.
Another point to note is that infrared beams won't penetrate walls or objects, so in this kind of network, each room will need its own antenna array. That might make it less practical for households – although the team does say that the setup should be fairly inexpensive – but could be perfect for businesses, where regular Wi-Fi is vulnerable to remote hacking. Interference from neighboring networks should be reduced, too.
While the system is mostly theoretical for now, the team says it could start to show up to connect video monitors, laptops and tablets in about five years' time. Researcher Joanne Oh received her PhD for the study last week.
