Is LiFi ready to switch on city services?

Light-based networking systems are already seeing pilot deployment in city projects, but LiFi has potential in many urban scenarios

LiFi, Wayfinding, LED lighting, Visual light communications

Practically all smart city projects are reliant on some degree of connectivity, and many city scenarios call for faster, cheaper, more reliable and more pervasive communications than are readily available at the moment. But while telecoms companies and equipment manufacturers are busy promising that the next generation of cellular networks will be the answer to all smart cities’ growing connectivity requirements, another technology is stepping into the spotlight as an alternative to radio frequency-based solutions.

Light fidelity, LiFi for short, uses light to transmit data instead of radio waves. An LED light, pulsating millions of times per second, either using light visible to the human eye or nearby on the light spectrum such as infrared or ultraviolet, can carry data at much greater bandwidth than radio frequency, albeit with limitations, making LiFi an ideal technology to complement or replace WiFi and cellular communications.

The technology is relatively new — the term LiFi was first used in 2011 — but it is gaining ground in a number of smart city pilots. The technology itself has been in use in some applications for as much as ten years, but it’s utilisation is slowly increasing, and in a number of fields, it is close to uncovering its killer app, all without attracting very much attention of the major network vendors.

There a number of different factors that make LiFi an attractive proposition. Primarily, it is a question of bandwidth. Li-Fi is capable of much faster transmission than WiFi, theoretically up to 1Tbps speed, and the current lab tested record is 224Gbps.

Oledcomm, one of only a handful of companies producing LiFi equipment, has demonstrated a commercial LiFi solution, LiFiMax, that offers 100Mpbs download speed, 40Mbps upload speed, and up to 16 simultaneous users from a single access point.

Light transmission is also far more stable than radio, making it ideal where a consistent connection is required, and LiFi offers latency that is a factor of three times lower than Wi-Fi, which give it application potential in areas where connectivity is essential, such as automation.

LiFi networks have a theoretical range of almost 200m and could even work underwater, although examples like Oledcomm’s LiFiMax are closer to 30m maximum range. They do require an uninterrupted line from transmitter to receiver, although it does not need to be direct — LiFi signals can be reflected off of surfaces and still retain speeds of up to 70Mbps. The technology works indoors and outdoors, even in bright light conditions, and in outdoor deployments, ranges of up to 50m can be achieved, even in poor weather conditions.

LiFi signals cannot penetrate walls or windows however, and anything blocking the light beam — such as a hand placed over the receiver dongle or USB key — will break the signal. This could mean that in some buildings more access points are required to create a network than an equivalent WiFi deployment, but it is also another selling point for LiFi. No penetration of walls means that, unlike RF networking, a person — think ‘hacker’ — outside of the building or room cannot intercept the signal, making it an attractive proposition for deployments that require higher levels of security. When coupled with encryption technology, LiFi is touted as a far more secure proposition for a wireless network than WiFi. The security capabilities of the technology have already attracted the interest of the Federal government of Canada, which is looking at secure phone systems using LiFi.

There are other plus points for using light frequency as opposed to radio. Radio frequency requires licensing, which can mean issues in some countries, while LiFi equipment requires no such authorisation.

The RF frequency is also highly crowded, with limited amounts of spectrum available. Because communications like 5G are restrained to certain bandwidths, they can face issues in environments where a large number of people are trying to connect at once, making LiFi a possible complementary technology in such scenarios. The visible light spectrum is also far larger — 10,000 times larger — than the radio frequency spectrum, meaning there is much more room to grow.

The fact that LiFi is not reliant of RF also makes it desirable as an alternative in environments where radio interference is a problem. In hospitals, RF can interfere with patient monitors and other healthcare equipment, and in some industrial settings, like mining, or refineries, radio interference can even trigger explosions. LiFi is proposed as a safe alternative in these scenarios.

While it is contentious, there are also concerns about the possible impact of RF waves on human bodies. Such concerns have led to bans on WiFi in some sensitive environments — for example, France banned WiFi in nurseries in 2015 — creating another opportunity for LiFi as a replacement technology for situations where concerns about RF are foremost.

Olav Scholte, Strategic Alliances and Public & Government Affairs at Signify Middle East, commented: “Do we want to live with all these electro-magnetic waves around us or do we prefer to get rid of all of those? When we have WiFi, we don’t have just one network, we have a lot of networks. LiFi is just data coming through light.”

Riding on the LED upgrade wave

The other big factor that is influencing LiFi adoption is LED lighting. In its current form, LiFi requires an LED to transmit. While most LEDs are not LiFi-enabled, requiring an appropriate chipset to be built in to the luminaire (light fitting), there is of course a huge amount of momentum in the changeover from traditional lights to LEDs. Some estimates say there are as many as 14 billion light points in the world being replaced by LEDs — which LiFi proponents say is a huge opportunity to ensure that those new LED luminaires can play a dual role in providing network coverage as well. Professor Harold Haas of the University of Edinburgh, one of the pioneers in LiFi, has said that potentially every LED lightbulb could become part of a LiFi network.

By deploying luminaires equipped with LiFi, and connected through Power over Ethernet (PoE) to the network, building owners or operators could potentially eliminate the need for a separate WiFi infrastructure to deliver connectivity to an office, store or mall. At a city or municipality level, light poles that are being converted to LEDs can potentially have LiFi built in, creating a high-speed data network at street level, free from RF or spectrum issues.

Signify has a number of pilot projects for LiFi, says Scholte.

There is already uptake of this form of light communications, albeit in its one-directional format, usually referred to as Visible Light Communications (VLC). VLC is being used to broadcast information one way, in use cases such as tourism or retail, and because signals can be received by the camera on a smartphone, the cost of deployment is attractive. As towns and cities upgrade to LED street lighting, LiFi companies are advising that it makes sense to ensure that the street lighting can be adapted for LiFi or VLC in future.

Benjamine Azoulay, CEO of Oledcomm, explained: “Generally the companies that are moving from conventional lighting to LED are today also considering implementing VLC at the same time, because for $10-15 per luminaire, you can add VLC, so the additional cost is really affordable. We see more and more big retailers adopting it.”

There are reservations about the technology, however. Gartner analysts Nick Jones and Bill Ray warned in a research note last year that there are a number of factors which meant they could only recommend it for pilot projects where LiFi has a specific use case advantage that WiFi or cellular cannot deliver, until at least 2020.

Gartner quotes lack of clarity on patents and standards, an immature market, and complex and expensive deployments that require specialised access point hardware to get the high bandwidths promised, as restricting factors, along with a lack of end devices that are natively enabled for LiFi.

Azoulay said that these issues are being addressed, although he suggests that at the moment LiFi is somewhat ‘flying under the radar’ while the telco and networking giants are busy with 5G.

The industry is organising, with entities like the ewly-formed Light Communications Alliance attracting membership from some of the leading names in communication vendors and operators.

The technology has also undergone high-end technical testing for disaster resilience, in tests conducted in the US last year by Verizon, Nokia and Aegex Technologies among others. LiFi’s use in rescue communications and emergency response is particularly interesting in environments where RF frequency is not suitable, such as where there is risk of explosion. The testing, which tried LiFi in a simulated subway accident, showed the technology performed well even in adverse conditions.

There are some commercial LiFi solutions on offer, although devices like smartphones and laptops with native LiFi have yet to emerge.

Pure LiFi, another LiFi specialist vendor, has demonstrated a standard HP laptop with embedded LiFi, at Mobile World Congress in February. In the absence of widespread adoption of this sort of embedded technology, however, OledComms LiFi still requires a laptop dongle, while Lucibel’s solutions use a USB key.

Prices are coming down — the OledComm LiFiMax set up of a single AP and dongle is available for $1,000, although Azoulay expects that price to fall as much as threefold in 12 months.

Azoulay added that the publication of the IEEE’s 802.11bd standard, which will cover LiFi, and is expected in 2020 or 2021, will likely kick-off a wider roll out of LiFi ready devices.

“We are still waiting for the standards to be published, the 802.11bd, before seeing the first smartphones and laptops being embedded with LiFi… this dongle is still an obstacle to massive penetration of the market, so for the moment the use cases are very specific,” he said. “We expect the first milestone will be in two years.”

The ecosystem and applications are emerging to make LiFi a major technology, says Azoulay.

Lighting up the city

In the meantime, the early deployments and pilot projects are beginning to increase in numbers and momentum.

Schultze said: “We are still in the early stages, but we are already seeing interest in new applications and enormous potential for LiFi to provide value beyond illumination.

“Together with our customers, we are currently in discussion or setting up pilots all around the world, including the UAE, to let the end-users experience the benefits of LiFi. These small-scale pilots will give the customer the opportunity to evaluate LiFi technology, learn about the use cases and potential infrastructure for their future renovations or new-builds.”

Signify is working with more than 30 customers in Europe, North America and Asia to pilot LiFi, Schultze added, with customers and partners deploying test labs and facilities, such as managed officers provider Incubex in Bangalore; IT infrastructure company Atea in Stavanger, Norway; and telco Orange in Paris.

Singapore’s Republic Polytechnic will install LiFi in its Smart Devices Lab to get students to start working with the technology, making it the first higher learning institute in Southeast Asia to adopt LiFi.

In the UAE, Hamdan Bin Mohammed Smart University (HBMSU) has a Signify LiFi-equipped campus that offers services such as smart wayfinding, to direct students to classrooms using an app.

One of the main areas of interest for LiFi, and VLC, is in using VLC to broadcast information services. Because VLC only requires the end device to receive a signal, not transmit, the standard camera on a smartphone can be used to read and receive the signal (so long as the device is not in a pocket or bag). This has a lot of potential in deployments such as city apps, tourist information, outdoor museums or walking trails, and retail locations.

In these situation a street fitting like a light pole/lamp post, or an indoor information point or retail display can be fitted with an LED emitter, and then as the user comes near, the content on their phone is activated.

UAE supermarket chain Aswaaq is using Signify’s VLC technology in its stores to broadcast special offers to shoppers who have downloaded its app to their phones. The app, which is part of the chain’s loyalty scheme, gives customers optimal route guidance through stores to the items they are looking for, and can even provide recipe suggestions based on their shopping list and location.

Oledcomm has already completed a pilot project using VLC on the Paris Métro, where the busy station for La Défense business district has been using it to broadcast information to travellers. RATP, the transit authority, has plans to deploy VLC across other stations as it switches over to LED lighting across its network.

OledComm has similar projects in Palaiseau, a city south of Paris, where it is being used to provide information via light pole to a residents’ app in a new eco-friendly residential development. In Reims, in the Champagne-Ardenne Region of France, the city centre is equipped with a VLC app to create an outdoor museum for visitors as they tour around the city.

The main learning from projects such as these, said Azoluay, is that the LiFi technology works perfectly — and the challenge for city authorities lies more in providing rich content that is up-to-date.

There are other use cases that are also still emerging, including situations where LiFi can complement other technologies like 5G.

One such scenario is connected cars, where Oledcomm sees interest from car manufacturers to have LiFi as a cost-effective and reliable means of connecting to road infrastructure. It’s high level of reliability and low latency make it an ideal solution as a redundant system or support to RF solutions.

“5G is coming but there is the phenomenon of saturation of radio frequency,” Azoulay said. “If you are in a stadium for instance, the radio frequency is totally saturated because of density of devices trying to connect at the same time. We know this is a limitation, 5G has started to get millimetre wave technology [to overcome this], and LiFi is seen as a complementary technology that will enable decongestion of those networks.”

A potential ‘killer app’ for LiFi is for onboard connectivity for airplanes. In the current scenario, all copper wiring on a plane needs to be shielded, greatly adding to the weight. Azoulay said that demonstrations are in the pipeline showing how a plane could be connected using a combination of LiFi and fibre optic cabling, which could deliver 100Mbps connection to the seat for each passenger, while removing as much as half a ton in weight from the plane and eliminating RF interference completely.

“Personally, I think that LiFi will be a major technology,” he said. “There are many examples of technologies that have taken their time to find a killer app. NFC for contactless payment, took 15 years before massive adoption in smart phones. You need a full ecosystem to adopt it — NFC was adopted because banks supported it — and the conditions for LiFi to emerge as a mass technology are also emerging step-by-step.”  

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