Light is everywhere in the modern era – we have turned night into day and live at a frantic pace compared to the sun-bound lives of our ancestors. But what if artificial light could be used for more than illumination? That question was asked by professor Harald Haas, chair of mobile communications at the University of Edinburgh, and his work has given us LiFi – a wireless access technology that uses light rather than radio waves.
The task of bringing this technology to the mass market now falls on Alistair Banham, who became pureLiFi’s CEO in July 2016. “When I was approached by the company it was clear that there was a very innovative team. I knew I could make an impact and bring experience that would complement their existing skills to develop pureLiFi into a world-leading company,” says Banham.
He adds that since he joined he’s focused on “developing a clear strategy that is understood and embraced by the whole team. Creating the right culture and organisation, with a clear focus on technology/engineering development and global customer engagement, has also been a priority. I have added key talent with strong global industry experience to the team to help drive the company to the next stage.”
LiFi uses a ceiling-mounted access point to modulate the brightness of the light from a LED lamp faster than the human eye can see. The signals are received by a photo-sensitive USB dongle connected to a user device such as a laptop (within a 60-degree cone from the ceiling-mounted transmitter), which can transmit back to the access point using infrared. The technology is full duplex, meaning that both the access point and dongle can transmit and receive simultaneously, at an impressive 42 Mbps. If more capacity is needed on the downlink side to support many users in the same room this can be provided by increasing the density of access points. LiFi can work in direct sunlight or with the LED lights turned down so low that the room they’re in appears dark. Power over Ethernet is the preferred means of backhaul, with power line communications being the best option for retrofit deployments.
Banham says that pureLiFi’s products are currently in their third generation, with a fourth due to be launched in the third quarter. He adds that it “will be 70 per cent of [the volume of] our current product… it’s half the height and width and a reduction in length, it’s almost like a thumbnail USB stick”.
There’s more to come. “[We’re going to develop] a series of products over the next two or three years that will enable us to provide individual components that can be embedded into OEM companies’ products… with the right cost and the right integration aspects they’ll enable us to drive mass market [LiFi] adoption,” Banham explains. He adds that one of the biggest challenges for his team was ensuring that LiFi is lamp-agnostic and that this required a lot of work with various LED manufacturers. “We don’t want people to have to buy custom LED lamps; they can buy one off the shelf.”
Banham wouldn’t be drawn into talking about any work pureLiFi might be doing with handset manufacturers, despite recent reports in other media outlets that iOS’ library cache file mentions ‘LiFiCapability’. However, he says “our goal is to develop components that can be integrated into handsets and tablets and laptops. We will be providing solutions to enable major handset and tablet manufacturers to adopt our technologies.”
Banham adds that “LiFi is additive and complementary to Wi-Fi, it’s not going to replace it”, and that “all the backhaul and all the technology that is used for 802.11 is the foundation for LiFi, we’re just adding to that to make sure [LiFi] is interoperable”. Speaking of spectrum, the visible part of the electromagnetic spectrum is in the 400 to 790 terahertz (THz) range. To put that in perspective, even at the low end of that scale it’s roughly a million times higher in frequency than UHF and nearly 14,300 times higher frequency than 28 GHz, one of the bands earmarked for 5G deployment. This suggests that offloading onto LiFi may be of use should data demand from 4K video and other sources become so great that the RF spectrum gets congested.
While LiFi is hardly the first time humans have used light to convey information, its late arrival into a world where wireless data transmissions are often tightly controlled poses some questions for regulators. However, as it works with visible light (which can be blocked with opaque objects) interference concerns may not carry the same weight as they do with RF. In Singapore, where LiFi is being trialled, “they’re looking at regulating LiFi but making it unlicensed, following the same path that Wi-Fi did”. However, Banham points out that “light is used in every country, I don’t think you’re going to have these specific unique elements that you have with RF spectrum regulations.”
While LiFi is not strictly a line of sight technology (because light bounces off surfaces) this has some benefits as far as security is concerned, because light can be contained by shutting doors and windows. In addition, LiFi can use existing security protocols for encryption and authentication. Perhaps it’s no surprise then that BT is working with pureLiFi to evaluate the use of its technology in the defence sector. “Because of the security aspects of LiFi it provides a good environment where they can remotely transmit data when they’re out in the field,” Banham says.
He adds that because each LED light with an access point has its own IP address LiFi enables the position of user devices to be tracked to within a few feet, allowing them to be sent location-specific information. He sees significant opportunities for this technology as part of location-based services. Another possible application is vehicle to vehicle communication, especially given that “a lot of cars have LED front and rear lamps”. “Imagine you’re in a line of traffic and a car five cars in front puts the brakes on to avoid something or stop, then you get this signal sent tail-light to head-lamps and if you’re the fifth car in line you’ll get a message that says ‘slow down there’s a potential problem ahead]’,” Banham describes. In addition, with “all these street lamps being moved over from sodium to LED we’re being requested to provide solutions to support information flow from the LED lamp to vehicles. We see a whole raft of new use cases [in this area over] the next five to 10 years.”
Banham adds that other potential uses include environments where the use of RF is frowned upon, such as intensive care units in hospitals, or that currently use intrinsically safe radio equipment such as oil refineries. He also thinks LiFi might have a role to play in manufacturing facilities where a lot of carbon fibre is used, given that RF doesn’t transmit very well in such environments.
Getting a technology start-up off the ground is no mean feat, particularly when that technology is a new player. “It’s a tough environment, you have to stick with your strategy and obviously evolve it, but you can’t keep changing it every two minutes,” Banham reveals. “You set your goals, define your strategy, then you work hard to get there. The other thing is that it’s not going to be success all the time, you’re going to have some bumps in the road that you must get over. Stay positive and stick to your plan.”
With many potential applications, a user experience practically identical to that of extremely fast Wi-Fi, and freedom from the relative confines of RF spectrum, LiFi is certainly a technology worth keeping an eye on. pureLiFi’s team are intent on making it as just as much part of everyday life as Wi-Fi. Who knows – perhaps it won’t be long before you’ll be downloading the latest issue of Land Mobile from the lights in your ceiling.
CV – Alistair Banham
Banham is a global semiconductor industry veteran, having led international business units for more than 30 years. Prior to his current role as CEO of pureLiFi, he was senior vice president & GM of Customer Solutions Business Unit at Wolfson Microelectronics, responsible for chip development, mobile systems strategy and driving engagement with tier 1 global accounts. Banham held roles as SVP & general manager EMEA (Europe Middle East & Africa) at Philips Semiconductors. He was a founding member and President & GM EMEA of ON Semiconductor and played a leading role in its spin out from Motorola semiconductor and IPO.
