Light-Wave Communications Said Key to Safer Communications, IoT

There are two different views of what Li-Fi is, developers said. One, developed by Harald Haas, professor of mobile communications at the University of Edinburgh Digital Communications and Li-Fi Center, involves the use of visible light communications (VLC) from light-emitting diode (LED) light bulbs. Haas coined the term “Li-Fi” in 2011. The second, backed by Walter Kraus, founder of IbsenTelecom and chairman of the Li-Fi Consortium, uses the infrared part of the light spectrum.

Haas’ version is not a point-to-point communications link with one transmitter and one receiver, he told us. He and his company, pureLiFi, see the technology as a networked system with a central transmitter (the light bulb) as an access point to sensing devices. Kraus’ Li-Fi vision is laser-supported. It uses signals in the infrared frequency range and involves a beam running between a transmitter and a receiver that must “see” the transmitter. Haas objects to how the Li-Fi Consortium uses the term, saying Kraus means infrared free-space optics, not Li-Fi in the sense that Haas intended it.

There’s a great deal of interest in the security aspect of Li-Fi from public agencies and companied concerned with secure communications, such as corporate headquarters, hospitals and others, Haas said. He said organizations don’t want to use Wi-Fi because the signals can be intercepted off-premises, but with Li-Fi, the signal doesn’t leave the room. Signals from mobile devices in the room are directed at the LED light bulb overhead, with a range of nine square meters (about 100 square feet), he said. In principle, the signal can be transmitted out a window but because it can’t bend around corners, any would-be hacker could be seen staring into the room, he said. In a closed room with no windows, communications would be completely confidential, whereas Wi-Fi can’t be contained, he said.

The infrared system can’t use strong signals because of Infrared Data Association rules about potential harm to eyes, said Kraus. So his focus area, where the beam meets the receiver, must be very weak, plus there are definite ranges for how far the beam can travel, he said. That has a “huge effect” on security of communications, because while LED light shines in all directions unless focused, the infrared technology is bundled through a laser into a particular direction, making the signal unreadable from outside that beam, he said. A hacker would have to be in the room and get between the transmitter and the receiver to intercept the signal, he said. The signal could be intercepted if the laser beam were sent outside a window, but the hacker would be in view, and the signal would eventually peter out, he said.

Impact on IoT

Li-Fi’s biggest economic impact will come with IoT, Haas said. Li-Fi is an emerging industry as large as mobile communications, and can transform economies because it can enhance how people live and interact, he said. It’s a disruptive technology that affects all industry sectors, offering unregulated, free bandwidth with no health concerns, he said of his version of Li-Fi. VLC communication uses include health monitoring. A patient could wear an earring that transmits to the nearest light bulb, allowing continuous monitoring of his health data, Haas said.

Many machines in the IoT will need high bandwidth connections, but not household items such as refrigerators, said Kraus. His technology focuses on high-bandwidth uses, he said. It’s similar to Wireless Gigabit (WiGig) technology, which uses radio spectrum and can transmit high gigabit rates but is subject to high error rates. Kraus’ company has demonstrated a transmission rate of 10 Gbps in the lab, much higher than the 3 Gbps that WiGig might reach in a few years, he said. The technology will come to market as a dongle that can be connected to the ethernet, USB ports and so on. The beam will be shone on a wall, and network connectivity will take place in its focus area with the use of a second device connected to a computer, phone or other equipment, said Kraus.

Infrared Li-Fi can be used to deploy information technology networks, said Kraus. His system could replace cable in buildings, potentially saving a great deal of money, he said. One center point in front of the building would send laser beams to different offices separately through the windows, he said. Another potential user group is hospitals, where Wi-Fi can’t be used because it interferes with equipment, he said. Li-Fi has no electromagnetic compatibility issues, he said. Wireless mic and camera users are also interested in the technology because it could do away with the need for cables, he said. Li-Fi, with its high bandwidth, could replace the high-definition multimedia interface normally used in homes for watching high-definition films and TV programs, he said.

Challenges

Companies such as Casio, GE and Philips are beginning to integrate Li-Fi technologies into their products, said MarketsandMarkets’ Nigam. Challenges remain, she said -- mainly that the technologies are direct line-of-sight, so they can only be used indoors. Additionally, people aren’t yet aware of Li-Fi, so there’s no consumer demand, she said. Because the technology is still in the research and development phase, it’s not commercially available, she said.

Li-Fi will be used in airplanes, operating rooms and other places where radio spectrum can’t be used, Nigam said. VLC can also be used in the automotive, in-flight entertainment, and underwater communications sectors, she said. Li-Fi will be as ubiquitous as Wi-Fi, but will be used in more applications, she said.

But Mavrakis said Li-Fi isn’t the next best thing, nor is it new. Infrared technologies used to be incorporated in laptops and phones, but they “went nowhere,” he said. From a technology perspective, Li-Fi is interesting, but from a practical and technical viewpoint it’s not very marketable, because Wi-Fi is readily available, cheap and pretty secure, said Mavrakis, who said his Ph.D is in infrared technology. Li-Fi could work for niche applications such as high-speed and high-security communications, but not for the IoT, he said.

Li-Fi and infrared technology can be very powerful, but will find it hard to break into the market either for secure communications or the IoT, Mavrakis said. Technologies more practical than Li-Fi have come and gone, he said, adding “I'm happy to be convinced otherwise.”