• 10.14.13

What Real-Time Wi-Fi Feels Like

Wireless radio communications are about to become nearly real-time with a new 100-gigabit-per-second technology.

What Real-Time Wi-Fi Feels Like
[Image: Flickr user Richard Flink]

Just how fast is “real time” wireless? Imagine an entire Blu-ray disc worth of data could be communicated between a transmitting device and receiving device in about two or three seconds. Or the entire memory contents of your typical iPhone could be dumped to a storage system in about a second or so. News that researchers at the Karlsruhe Institute of Technology have achieved an experimental wireless transmission rate of 100 gigabits per second will make it possible.


The prototype system is called Millilink, and as you may expect from an experimental technology, the range was pretty limited–just 20 meters inside the lab. It works in a rather stunning way, combining both radio signals and laser photonics. Two different frequency laser signals are mixed in a “photo mixer” chip by being captured on a sensitive photodiode, which then generates an electrical signal based on the frequency difference of the two incoming signals. The resulting high frequency signal, at 237.5 GHz (basically 2,000 times higher frequency than your typical FM radio channel), is sent on to an antenna. The data signal that is transmitted is encoded on this carrier wave by modulating it, using fairly typical methods.

And this is where the use of the system becomes most obvious–if it finds its way into commercial devices sooner rather than later, it’ll be used to help bridge difficult gaps in fiber optic networks, like those being installed to bring broadband to the wilder parts of the world. This is because its input signals are optical and can just be taken in a bit-transparent way from typically the light flowing through fiber optic data links. Rather nicely the tech uses some fairly simple and robust devices–which means it’s not necessarily many years from production.

But the same team has already used similar but electronic-only technology to transmit data at 40 gigabits per second over distances of a couple of kilometers, and this is much more likely to have consumer-grade uses. How would you like your home router to connect to the nearby ISP tower using this sort of tech, at 40 gigabits-plus a second?

And here’s the kicker: The team at KIT thinks it can multiplex different streams of data together cleverly and transmit it over multiple antennas, similar to the multi-antenna solution of 802.11 N. With some finesse, this should mean their electro-optical antenna could manage data speeds of about 1 terabit per second. Given the massive data requirements that 4k TV may involve and the knowledge the average home is consuming ever more broadband all the time, it sounds like this tech is going to be needed.

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