One of the many mysteries that are central to the plot of Sir Arthur Conan Doyle’s Sherlock Holmes novel The Baskerville dog They are mysterious lights that appear on the moor, a piece of wilderness where Baskerville Hall is located. These lights are in fact encrypted messages from a man hiding in the bog signaling to his sister in the manor.
More than a century after this novel was written, the concept of conveying information through light remains fascinating – albeit on a level that even Sherlock Holmes found difficult to predict.
The technology in question is Li-Fi, a form of wireless communication that uses very fast pulses of light to transfer data between devices. The sales pitch for the technology, which the German physicist and Li-Fi pioneer Harald Haas presented to the world in 201
This has several advantages, but the big one is the extraordinary amount of data that can be used to transfer it. An early demonstration carried out by researchers at the Heinrich Hertz Institute in Berlin showed data rates of more than 500 megabytes per second with just a standard white light LED. Things have improved a lot since then.
However, people are still waiting for Li-Fi to become the mainstream technology that its proponents believe should be.
In the simplest case, Li-Fi works by switching the zeros and ones that classic computers speak on or off in two light states. When an LED light is on, it sends a digital one. When it’s off, it sends a digital zero. By turning these lights on and off extremely quickly, it is possible to send messages at an amazingly high speed, much like the characters in The Baskerville dog signaled together at night. Just a lot faster.
So fast, in fact, that what is technically a flickering light appears to be constant to the human eye. This is similar to the way the human eye does not see the break between frames of the film when viewing a projected film. However, this high speed not only prevents the Li-Fi lightbulbs from flickering. By flickering at the speed they have, they also allow enormous amounts of data to be transferred.
“[Li-Fi] can use an enormous bandwidth in the optical spectrum, ”Harald Haas, Chair of Communication at the University of Strathclyde in Glasgow, told Digital Trends. “This is three orders of magnitude larger than the entire radio frequency spectrum, which means you can send and receive one amount of files. LiFi offers a massive data line compared to the limited data line of RF. “
“Since, unlike radio signals, light cannot penetrate opaque objects such as walls and doors, Li-Fi could also be used to build secure wireless systems.”
However, this is only one potential benefit of Li-Fi. In contrast to radio, Haas also points out that with Li-Fi, the available spectrum over which it is transmitted is unregulated and free. This could allow unrestricted use of the same spectrum in every country, which could lead to easier global standardization that could reduce costs and complexity. In addition, it is resistant to electromagnetic interference (EMI), so both RF and Li-Fi systems can be used in close proximity without interfering with one another. This would be particularly useful in dense urban environments where many mobile devices require high-speed data connections that interfere with one another. With the advent of Internet of Things (IoT) devices, this problem will only get worse.
Since, unlike radio signals, no light can penetrate opaque objects such as walls and doors, Li-Fi could also be used to build secure wireless systems. Finally, the lack of an antenna requirement means that it can be useful in scenarios like chemical or nuclear power plants, where the slightest spark could potentially cause an explosion.
So why the use of weasel words like “may”, “could”, “could” and a selection of others? Because Li-Fi is not yet mainstream. A decade after it was first revealed, it’s still a work in progress. A flickering light in your home is more likely to be a bad connection than a hyperspeed data connection that can download an entire series of a Netflix show in less than a minute.
“The technical barriers are mainly in the efficiency of the conversion from optical to electrical,” said Haas. “This means that we need advanced transceivers to take full advantage of the spectrum available.”
There are, it should be noted, one or two other possible pain points. The range is closer to 10 meters compared to 32 meters with normal WiFi. Nor can it be used in bright sunlight for obvious reasons, although it can be burned into street lights to provide nighttime public WiFi along with lighting. But Haas remains confident that Li-Fi is actually on its way. “I can see a world where Li-Fi is built into a smartphone along with all other RF technologies,” he said.
He points to the significant advances Li-Fi has made over the past 20 years. In the early 2000s, the data rate from white LEDs was around one megabyte per second. Today that number is closer to one gigabyte per second.
“In the past, LEDs were designed primarily to improve the efficiency of converting electrical to optical power,” he said. “Now we see that LEDs have also been developed to improve electrical bandwidth, which is a key parameter for fast data communication. There are also new white light sources based on lasers that deliver 10 Gbit / s. This is a factor of 10,000 improvements over the past 20 years. This trend will continue. “
Will it become mainstream technology?
While Li-Fi is not yet mainstream technology, it doesn’t fall into the sad niche of laserdisc, lossless digital audio tapes (DAT), or other proven superior technology that (at least in the eyes of the general) went to the grave publicly) without convincing the masses that they were as big as they actually were. Development continues and if Haas has its way, all you have to do is wait for it to appear (no pun intended).
“Of course this will happen,” he said. “Li-Fi become become a mainstream technology. I have no doubt. I think people need to understand that this technology is fundamentally different from any wireless technology in existence. [That] means that the ecosystem for this technology is still mature. This is evolving as we educate the markets about the great benefits of this technology. It takes time to build the ecosystem and ensure the broader support needed to make Li-Fi mainstream. “
Reece Williams, a li-fi expert on the site LiFi.co said he believes Li-Fi will play a certain role in the future. “While [it] It may not, and is unlikely to, completely replace Wi-Fi. It will most likely be used as a complementary technology, ”Williams told Digital Trends. “Li-Fi and Wi-Fi could complement each other and unlock the full potential of technologies such as the Internet of Things, as well as virtual reality and augmented reality. “
Now the rest of the world just has to see the light.