The recent ratification of a Li-Fi standard by the Institute of Electrical and Electronics Engineers (IEEE) could finally push the optical wireless technology into a widespread datacom presence alongside Wi-Fi. Whether or not it does, this much seems sure: The IEEE has assured an invisible Li-Fi future.
Invisible, that is, as in the electromagnetic spectrum that Li-Fi vendors and operators will deploy to deliver the internet to phones, laptops, and tablets. The new IEEE 802.11bb specifies the use of infrared lightwaves, LEDs Magazine has learned.
That means that Li-Fi has moved away from its early incarnation starting more than a decade ago, as a technology that would use the visible light spectrum from a room’s LED lamps or luminaires. It has morphed into a system that uses IR emitters. Infrared is the part of the spectrum with waves longer than visible red and is often referred to as “invisible light.”
“The wavelengths defined are IR, so no visible sources are covered by the standard,” affirmed a spokesperson for Edinburgh, Scotland–based Li-Fi pioneer pureLiFi, in elaborating on 802.11bb.
The reshaping of Li-Fi as an IR play rather than a visible-light one has been happening for a while. By now codifying it in a standard that has been a long time in the making, the IEEE has increased the chances that Li-Fi vendors will market gear that has nothing to do with illumination.
“It is important to note that not all Li-Fi systems will be part of lighting systems,” the pureLiFi spokesperson told LEDs. “Some access points may be integrated with Wi-Fi or cellular access points, for example.”
French Li-Fi vendor Oledcomm has already firmly moved in that direction, albeit not via the IEEE approach but via a rival Li-Fi scheme endorsed by the International Telecommunication Union (ITU). As LEDs reported last October, Oledcomm no longer works with luminaire makers. Instead, it focuses on selling IR systems into industrial, aerospace, and military environments. Its CEO Benjamin Azoulay has explained that modulated IR delivers data faster than does modulated visible light. He has also noted that in the niche market of airlines, passengers will object to having to switch on lights in order to use Li-Fi on their devices.
Like Oledcomm, Signify — another ITU adherent — has abandoned the direct use of visible light in its Li-Fi efforts in favor of IR only, although the transmitters could be attached to luminaires or independent of them.
As a general observation, a luminaire might include light sources that emit across the visible and invisible spectrum. In that case, the modulation of waves required for digital encoding would apply to the IR portion.
In pureLiFi’s case, the company has a mix of IR and visible light in its portfolio.
“PureLiFi uses both visible and invisible light (infrared) for communications,” it explains on its website. “For example, our Light Antenna ONE, the LiFi@Home system and the LiFi Cube system all use infrared for communications. Therefore no illumination is required for these LiFi access points to transmit data. For systems such as LiFi-XC and the Kitefin System that use visible light for communications, they require some amount of illumination to transmit data.”
The company chaired the IEEE committee that, after a marathon process beginning at least five years ago, was finally able to nail down the standard with long sought buy-in from chip and gadget makers.
With 802.11bb now approved, the likelihood increases that portable device makers will start to embed Li-Fi chips in phones, laptops, and tablets. Without such integration, widespread adoption will continue to elude Li-Fi, which is now into its 12th year of commercialization. Users generally have to attach USB sticks or other dongles in order to fire up Li-Fi.
PureLiFi’s infrared Light Antenna ONE is of note in that regard. It is a set of chips designed to fit inside phones and other devices to enable Li-Fi communications.
The existence of a rival ITU standard — backed by Signify and Oledcomm — could undermine broad uptake if the lack of a single standard causes users, gadget makers, and other members of the value chain to balk.
But pureLiFi is clearly encouraged by the prospects that 802.11bb brings, in large measure because it ensures interoperability with ubiquitous Wi-Fi, which is based on the IEEE 802.11 standard.
“The 802.11 standard is one of the most pervasive standards used in consumer technology such as smartphones,” CEO Alistair Banham told LEDs in an email. “This standard for which there are already billions of components integrated into a wide variety of client devices, for example (not limited to) laptops, tablets, home hubs, smart watches, televisions, head mounted displays, and many others. This removes a barrier to entry and makes it significantly easier for pureLiFi to integrate our technologies, including the Light Antenna Module into next-generation consumer devices.
“In summary, there are billions of 802.11 basebands in billions of connected devices that our technology can now interface with using this standard.”
Basebands are the transmitters that send signals to end-user devices.
However, Oledcomm’s Azoulay has pointed out that Li-Fi will require its own baseband chipsets, of which there are none yet generally available in the IEEE format, but which do exist for ITU devices.
“IEEE 802.11bb is a good step but will only be significant when the digital baseband makers (such as Intel, Broadcom, and Qualcomm) will integrate the 802.11b function on their roadmaps,” he said last week.
LEDs has been asking ITU enthusiast Signify to comment on the ramifications of 802.11bb for a week, but the company has told us that no one has so far been available. The reticence from one of the leading Li-Fi vendors strikes us as curious; we will report when they have more to say.
We’ve also asked Signify about any plans they might have to deploy laser Li-Fi. Lasers are faster than LEDs. Both pureLiFi and Oledcomm regard them as a large part of the technology’s future and have already started to use them, although LEDs should continue to play a role.
IEEE 802.11bb applies to both laser and LED technology.
Meanwhile, until device makers start to embed Li-Fi chips of any sort, cynics might say that the word “invisible” describes not just the technological wavelength, but also the prospects for robust business growth.
MARK HALPER is a contributing editor for LEDs Magazine, and an energy, technology, and business journalist ([email protected]).