Eindhoven Scientists Prep 100 Times Faster WiFi via Infrared – 43Gbps Per Ray

Before Bluetooth came along it was quite normal for early portable devices (PDAs, Smartphones etc.) to communicate via a short line-of-sight link using Infrared light. Now scientists at the Eindhoven University of Technology have used a similar approach to deliver a “100 times faster” WiFi style network.

Most traditional WiFi wireless networks harness radio spectrum signals via frequency bands of 2.4GHz and 5GHz, which have the distinct advantage of being able to penetrate around the home and through walls from a single distribution point (e.g. broadband router). However the signal does get weaker over distance and in busy areas there can be problems with network congestion.

By comparison Infrared (IR) based communication devices use electromagnetic radiation with longer wavelengths than those of visible light, which also means that the light it emits is effectively invisible to the human eye.

As mentioned above, IR based communication systems are nothing new and they’ve been used for short to medium range network connections before, although WiFi and Bluetooth have long since replaced many of those systems. Never the less we could potentially see a return to IR after researcher Joanne Oh developed a new WiFi style network system that can deliver speeds of 42.8Gbps (Gigabits per second) per IR ray of light, with each device getting its own ray.

In this setup the wireless data would come from a few central “light antennas” (e.g. mounted on the ceiling), which are able to precisely direct the rays of light supplied by an optical fibre. Apparently the antennas contain a pair of gratings that radiate light rays of different wavelengths at different angles (passive diffraction gratings) and changing the light wavelengths also changes the direction of the ray of light.

One key advantage of this approach / antenna is that it is “maintenance-free and needs no power.” However IR communications cannot penetrate through walls and so when somebody moves out of an antenna’s line-of-sight then another one would need to be installed in the next room in order to take over. Device location is tracked by monitoring the radio signal as it is transmitted in the return direction.

TU Eindhoven’s Explanation

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. Joanne Oh even managed a speed of 42.8Gbit/s over a distance of 2.5 meters. For comparison, the average connection speed in the Netherlands is two thousand times less (17.6 Mbit/s).

Even if you have the very best wi-fi system available, you won’t get more than 300 Mbit/s in total, which is some hundred times less than the speed per ray of light achieved by the Eindhoven study. The Eindhoven system has so far used the light rays only to download; uploads are still done using radio signals since in most applications much less capacity is needed for uploading.

Not enough context is given for the remark about WiFi being limited to a total speed of 300Mbps, which without further definition seems incorrect because multi-Gigabit WiFi networks are already available (even if you do have to be virtually sat right on top of the adapter in order to get that kind of speed).

Similarly the fact that you’d have to run a fibre optic cable to each antenna, in each room and then on top of that your uploads would still need to be “done using radio signals” makes it all seem like a rather complicated and ugly setup that people probably won’t rush to adopt. In some ways this seems like a step back from the alternative Visible Light Communication (VLC) systems that we’ve been hearing about for awhile (here).

On the other hand such a network would certainly be very fast, as well as being much more secure and it avoids the traditional problems of network congestion (every device gets its own ray of light, at a different wavelength). However you won’t be able to buy it anytime soon because the developers anticipate that it could be another 5 years before the technology is ready for commercial use.