4imprint, LLC

| Updated: January 18, 2021

LED light bulbs put internet in the fast lane

Imagine downloading a movie in one-twentieth of a second. With Li-FiTM technology—a potential replacement for Wi-Fi—it’s possible, at least in theory.

Li-Fi uses visible light—as emitted by LED light bulbs—to transmit data.[1] (To compare, Wi-Fi uses radio waves.[2]) Instead of connecting to a Wi-Fi network, you would place your device under a beam of LED light to capture and send data.

Li-Fi can send data at 1 gigabit per second, with a theoretical top speed of 224 gigabits per second.[3] Even if the theoretical speed doesn’t play out, the 1 gigabit per second rate still is 100 times faster than Wi-Fi.[4],[5] In short, Li-Fi could accelerate life on the internet as we know it.

This Blue Paper explores the origins of Li-Fi, how it works, its benefits, its applications, its drawbacks and what comes next for this technology—and your business.


The story of Li-Fi technology

Li-Fi is short for light fidelity, similar to how Wi-Fi is short for wireless fidelity.[6] German physicist Harald Haas shared the term Li-Fi with the world at a TED Talks® presentation in 2011. Haas, a mobile communications professor at the University of Edinburgh, demonstrated how lightbulbs could be used as digital routers by projecting a high-definition video—and interrupting its play by blocking the light source.[7],[8]

To make the case for Li-Fi, Haas pointed out that the demands on the radio spectrum, which enables Wi-Fi technology, are increasing. He reported that there were 1.4 million radio cell towers and 5 billion cell phones transmitting 600 terabytes of data monthly. When it comes to the Internet of Things (IoT), there will be 50 billion connected devices by 2020. Hass compared the need for internet connectivity to a utility, like water and electricity.[9],[10] And, the demand for the internet only has grown since Haas’ TED presentation. Recognizing this demand (and looking to capitalize on Li-Fi), Haas founded pureLiFi in 2012 with a group that has been studying the technology since 2008.[11]

According to Haas, expanding the internet only can work if it’s energy neutral. In a follow-up TED lecture on Li-Fi in 2015, Haas said global IT and communication technologies need about 100 nuclear power plants to work. And, as the need for the internet grows, there will be a greater call for energy.[12] Using existing infrastructure as much as possible, which includes using Li-Fi-enabled LED bulbs to transmit data, takes some strain off additional energy needs. The big idea is to replace incandescent and fluorescent lightbulbs with energy-efficient LED bulbs.

Haas and pureLiFi aren’t the only Li-Fi game in town. For example, the 100-times-faster-than-Wi-Fi speed that’s been covered in the media was recorded by Estonian Li-Fi firm Velmenni.[13] OledcommSM of France also offers Li-Fi products.[14] These and other Li-Fi outfits anticipate the market to heat up. The Li-Fi technology market is expected to reach more than $6 billion by 2018, with an annual mean growth rate of 82 percent.[15] As the market grows and competition ensues, there’s potential to see diverse offerings in Li-Fi technology, which could change the game for all internet users.


Getting to know Li-Fi technology

Li-Fi is similar to the infra-red technology in your remote control, except faster.[16] It’s a wireless visible light communications system (VLC),[17] which is high speed and bidirectional, meaning Li-Fi-enabled devices can communicate with each other.[18] Here’s a graphic that explains how Li-Fi works (Figure 1):[19]

How it works

An overhead lamp fitted with an LED with signal-processing technology streams data embedded in its beam at ultra-high speeds to the photo-detector. A receiver dongle then converts the tiny changes in amplitude into an electrical signal, which is then converted back into a data stream and transmitted to a computer or mobile device.

Graphic showing how Li-Fi works

Figure 1: How Li-Fi works

The basic gist of Li-Fi is this:[20],[21],[22],[23],[24]

  • An LED light is fitted with a Li-Fi-enabling microchip or connected with a Li-Fi access point unit. The unit or LED lamp would require hookup to an Ethernet cable.
  • The Li-Fi technology changes the amplitude of the light waves for data transmission. The light needs to be on to transmit data. But, you can dim the light until it appears to be off, and data still will be transmitted.
  • A receiver picks up the subtle changes in the amplitude of light. Constant light (light that doesn’t come from a special LED bulb) doesn’t have the amplitude change and doesn’t affect the receiver. For reference, pureLiFi’s receiver is “three-quarters of a credit card” in size.
  • A signal-processing element in the receiver “[converts] the data into ‘streamable’ content.”

While direct line of sight from the LED to the receiver is the most efficient way to transfer data, reflected light beams still could transfer 70 megabits per second.[25] Line of sight will make a Li-Fi signal stronger. But, as long as light particles can hit the receiver “it can receive data, albeit at a lower data rate if light levels are low.”[26]

The cost of Li-Fi technology is unclear. Haas’ pureLi-Fi has sold the technology to “limited corporate clientele.”[27] When asked about the cost of a Li-Fi-enabled lightbulb, Haas said, “That’s a question I can’t really fully answer because we are dealing with early-stage prototypes. The cost will be dependent on the volumes we are able to get. … Wi-Fi has a widespread deployment, so the costs are low.”[28] Until the market for Li-Fi further develops, budgeting for this technology will be challenging.


Benefits of Li-Fi technology                                                                                           

Along with blazing speed, Li-Fi technology has many other benefits. Li-Fi technology:[29],[30],[31],[32]

Increases security: Radio waves pass through walls. They can be intercepted by people with bad intentions. But, light can’t pass through walls; there’s only data where there’s light. With Li-Fi, data are more secure and there’s more control over emission of data. Each light fixture is a separate data channel, and each Li-Fi channel “can supply different data into each separate pool of light, delivered at the full rated download speed for that channel.”

Leverages existing infrastructure: In 2011, Haas said there were 14 billion lightbulbs worldwide—that’s 14 billion opportunities for data transmission with Li-Fi technology. An LED flashlight in a smartphone even could work for data transmission.

Boosts internet capacity: Radio waves are a finite resource. We only have so many of them, and we’re running out of spectrum as the demand for high-speed internet increases and the IoT explodes. To compare, the visible light spectrum that Li-Fi technology employs is 10,000 times greater than the radio wave spectrum. There’s room to grow.

Works with greater efficiency: LED lightbulbs provide illumination, and the data transmission comes for free, not to mention LED lightbulbs are highly efficient. LED output power is a programmable feature. That means when an LED Li-Fi access node isn’t serving users or receiving data from another node, the node can automatically hibernate its data-transmission properties and switch back to illumination only. What’s more, radio wave towers that support Wi-Fi technology need to be cooled—a process that’s highly inefficient.

The efficiency and potential infrastructure of Li-Fi technology are especially appealing as many organizations look for ways to reduce energy consumption.


Applications of Li-Fi technology

From toys that talk to each other to interactive retail displays to cars that avoid crashes, there are myriad applications for Li-Fi technology. Check out these exciting possibilities that could be coming to you in the not-too-distant future:[33],[34],[35],[36],[37]


Location-based services: Li-Fi is being used in location-based indoor positioning products, such as iBeacons™, which send signals to mobile apps on shoppers’ phones. In a retail setting, display lighting with Li-Fi technology could “transmit advertising information on the goods being viewed, as well as say special offers and coupons. This will allow the merging of the [brick-and-mortar] and online shopping experience, and provide novel retail business models to emerge. Catalog information, discount coupons and advertising videos could all be provided to shoppers.”

Content consumption: Downloading video and audio and livestreaming call for lots of download bandwidth but not much upload bandwidth. Moving this sort of internet use away from existing radio wave channels “[extends] cellular and Wi-Fi capacities.”

Smart lighting: Any lighting, public or private, could become a Li-Fi hotspot. Li-Fi sensors also could control data and lighting.

Mobile connectivity: Li-Fi could interconnect laptops, smartphones, tablets and other mobile devices. Short-range links deliver high data rates and security. Similarly, using LED lights, toys could “talk” to each other.

Underwater communication: Undersea vehicles could transmit data when they shine a light, which can travel long distances. Li-Fi technology could “enable communication from diver to diver, diver to mini-sub, diver to drilling rig, etc.”

Hazardous environments: Radio frequency communications cause electromagnetic interference, which could be bad news in mines and petrochemical plants. Li-Fi is a safe alternative.

Secure internet: Li-Fi’s unique security characteristics make it appealing for certain environments. For example, Li-Fi could be used in a hospital to transfer secure data from specific light sources and to deploy networked medical equipment—all while eliminating electromagnetic interference that comes with Wi-Fi. In a hotel, each room could be equipped with Li-Fi. Data cannot pass through walls because light cannot pass through walls, and the visible light spectrum “does not have to be shared among a large number of users in the rooms.”

Transportation: LED lights in vehicles, street signs and traffic signals could use Li-Fi technology to enable vehicle-to-vehicle and vehicle-to-roadside communication, improving safety and traffic congestion. Li-Fi could help program traffic routes “to realize smart cities.”

User recognition: A Li-Fi access node can be programmed to recognize users and their access privileges. For example, firefighters with access privileges could turn Li-Fi nodes throughout a burning building into cameras to search for trapped occupants.

Indoor navigation: Because an entire network of Li-Fi nodes is programmable, Li-Fi could be used for indoor navigation, directing travelers from each light source as they move through a facility. For example, lights along a hotel corridor or reception hall could transmit data. Nodes could track moving objects, such as personal assistance robots, and direct them to a location, such as a docking station.


Broadband internet needs support as the IoT continues to grow, and the many applications of Li-Fi demonstrate how useful this technology could be to businesses and consumers alike.


Drawbacks of Li-Fi technology

Li-Fi technology, despite its many benefits and applications, has drawbacks. Here are some hitches that could stunt widespread adoption: [38],[39],[40],[41],[42]


Blocked by walls: Li-Fi signals can’t pass through walls or ceilings. For Li-Fi to work, LED lightbulbs must be placed throughout a building.

Security concerns: The minimum distance for signal reception with clear line of sight is unclear. Because of this, a telephoto lens or an optical sensor could intercept data. The Li-Fi Research and Development Centre at the University of Edinburg points out minimal precautions to prevent data leaks through windows.

Maximum speed is unknown: The lab setup that recorded 224 gigabits per second was ideal—not a simulation of a real-world environment, with light pollution and other variables. 

No (or limited) outdoor use: Li-Fi does not work in direct sunlight, which means it cannot replace public Wi-Fi. But, “through the use of filters the technology can be used indoors even when sunlight is present.”

Energy consumption: LED lightbulbs also must be turned on for Li-Fi to work. This makes the technology a good fit for retail and industrial settings, where the people who need internet connectivity already have the lights on. But, Li-Fi could be challenging in homes for this reason. This being the case, “it’s not clear if the benefits of faster wireless communication will outweigh the costs of constantly on LED lights.”


The fact that Li-Fi can’t pass through walls—the quality that makes it more secure than Wi-Fi—probably is the technology’s greatest liability in terms of adoption.


What comes next for Li-Fi—and your business

Li-Fi technology hasn’t yet made it into the mainstream and it’s already evolving to incorporate solar technology. In his 2015 TED Talks lecture, Haas presented Li-Fi technology using solar cells as a receiver. He demonstrated how off-the-shelf solar cells can convert light into electrical energy to power computers, phones and other devices connected to the internet. Solar Li-Fi still is ultra fast, receiving 50 megabits of data per second, which is faster than most broadband connections. According to Haas:[43]

“What’s really important here is that a solar cell has become a receiver for high-speed wireless signals encoded in light, while it maintains its primary function as an energy-harvesting device.”

In the TED talk, Haas highlighted solar Li-Fi applications:[44]

  • Existing solar cells on a house could act as a receiver.
  • Translucent solar cells could be integrated in windows.
  • Solar cells could be integrated in street signs.
  • Solar cells could be integrated into devices that compose the Internet of Things.

This solar technology could come to market in two to three years, and it could narrow the digital divide across the globe, create more room for the Internet of Things and decrease (or negate) the energy needed to bring everyone (and every device) online.[45] Solar cells build on the energy efficiency of LED lightbulbs.

One of the biggest tech companies in the world—Apple—has its eye on Li-Fi. There was a reference to “LiFi Capability” found within code for Apple’s iOS 9.1, which means Apple may anticipate growing use of Li-Fi technology.[46] Apple also patented a Li-Fi-optimized image sensor. The tech firm could be looking at Li-Fi as it develops media services, such as HD video delivery, or as a way to help users get more out of current internet connections. Based on the timing of previous final deployments, the Li-Fi technology in a future Apple operating system could be available in 24 to 48 months.[47]

Li-Fi is just revving up for business owners, but don’t toss your Wi-Fi routers quite yet. It’s likely that Li-Fi and Wi-Fi technology will work together for a well-rounded experience. For example, Wi-Fi could be used for general use, and Li-Fi could be used for super-speedy hotspots.[48] A Computerworld® article holds that “Li-Fi is not intended to be a replacement for Wi-Fi, but a companion technology, presumably designed for home networks and IoT deployments.”[49] Li-Fi and Wi-Fi can work in parallel.

Li-Fi will appear gradually on the market. A French industrial lighting firm has built pureLiFi’s technology into its products, which are coming out in the third quarter of 2016.[50] But, Li-Fi technology for consumers is two to four years away.[51],[52] Widespread adoption of Li-Fi technology likely will take even more years after an introductory period. And, it’s likely the business applications for Li-Fi will evolve, too.

Questions, however, still remain about Li-Fi technology:[53]

  • Will users ever be able to access Li-Fi networks in the sun?
  • What’s the best way to set up a Li-Fi network across a business if connections must be within line of sight of a receiver for best data speeds?
  • How expensive will Li-Fi be in the beginning, and will the cost of the new technology slow mass adoption?

These answers will influence how and when business owners integrate Li-Fi technology into their organizations. The speed of Li-Fi is turning heads in a world that works more and more in the cloud, and energy-efficient LED lights—more and more common in light fixtures all around you—could give users a two for one deal: illumination and data transmission. But, the fact that Li-Fi is blocked by walls may relegate it to best supporting actor next to Wi-Fi. In any case, as more people and things demand connectivity, internet technology will continue to develop in the fast lane, shaping how we live, work and communicate with each other.


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