Li-Fi: Revolution or Utopia?

How was LIFI invented?

Radio waves are only part of the spectrum that can carry our data. What if we could use other waves to surf the internet?

German physicist Harald Haas has developed a solution he calls "data through lighting" by sending data through an LED bulb that varies in intensity faster than the human eye. It's similar to the infrared remote control, but much more powerful. This technology involves inserting a microchip into the LED bulb connected to an upstream transmission source (either fiber optic, PLC, or DSL).

Harald Haas wants to transmit data wirelessly from every light bulb: "Cleaner, greener, brighter..."

Presentation at the TED Conference in August 2011 by Harald Haas (pioneer behind a new type of light bulb that can communicate as well as illuminate – access the Internet using light instead of radio waves) – video of the world's first presentation of Li-Fi technology in August 2011.

Introducing pureVLC

Website of the French startup OLEDCOMM, born from the engineering lab at the University of Versailles Saint-Quentin, which produces, among other things, Li-Fi/VLC indoor geolocation devices with support from Philips.

Haas says his invention, which he calls "D-Light," can produce data rates exceeding 10 megabits per second (several drivers operate at 150 Mbps). He envisions a future where data for laptops, smartphones, and tablets is transmitted by light in a room. And security would be enhanced; if you can't see light, you can't access data. A multitude of applications are possible for this technology, from public internet access via streetlights to cars that communicate through their headlights. Li-Fi could facilitate wireless data transmission across the visible spectrum, allaying some users' fears about electromagnetic waves.

Li-Fi: A Technology for the Smart City?

In an exploratory vision of the Smart City, Li-Fi could be used in certain areas for urban street lighting, public transportation (metro, trains, planes, etc.), as well as medical or industrial environments where wireless radio communications are disrupted and/or dangerous. Advantages, but also disadvantages:

– Paradoxically, Li-Fi is energy-efficient because it uses lighting and consumes very little additional energy => It only works if the light is on, even dimly, but it must be on... which limits its use in public spaces!

– Li-Fi has a theoretical transmission potential much higher (x10,000) than wireless radio: it leverages the light spectrum versus the electromagnetic radio spectrum: The visible light spectrum is 10,000 times higher than the radio wave spectrum thanks to "LED/SIM OFDM" data transmission technology.

– Li-Fi is mono-directional (you can only receive and not transmit to the Li-Fi sensor), so interactivity is impossible unless coupled with another technology (e.g., PLC, WIFI, etc.), which limits its development: Much like the first satellite technologies (now bi-directional), users' terminals or connected objects cannot transmit. It therefore prohibits all transactional applications or those that require sending streams to the network (sending emails, VOIP connections, instant messaging, connecting to a professional or personal domain, etc.).
The uses of Li-Fi are, therefore, limited to pure signal broadcasting when no transmission is necessary. For example, geolocation inside a building or for broadcast-type services (downloading applications, documents, media content, viewing HD video streams, etc.) by “pushing” content to a tablet, a smartphone, etc. in all rooms of the house, in hotel rooms, in a professional location, in a commercial space, for the reception of a public service or when visiting an exhibition.

– Li-Fi offers a unique and superior level of security: the data stream is only accessible in the "direct beam" of light, unlike radio waves, which circulate in a less controllable manner.

– Li-Fi is only a technology for the last few meters: It requires the deployment of a collection network behind the "LED lamps," which requires a huge collection infrastructure to establish. Several avenues could combine PLC and Li-Fi in public lighting networks.

– LiFi requires replacing the current stock of light bulbs with LiFi-compatible LEDs: 14 billion bulbs worldwide. It's a huge market, but as with any innovation, we must not arrive too early or too late. We must start thinking about lighting for a building, a neighborhood, a means of transportation, a public space (metro station, etc.) right from the design stage!

=> In a first generation, LIFI could target industrial applications or specialized spaces: initially targeted (stations, subways, trains, tunnels, airports, airplanes, hospitals, factories, museums, convention or exhibition centers, etc.).

Wireless radio (Wi-Fi, etc.) will not be replaced by wireless light in 2014, but in 5 or 10 years, this technology could complement our range of "wireless" access tools, particularly in the field of proximity "broadcasting" (broadcasting of very high-speed streams in dedicated or modular spaces).

The most important industrial challenge remains convincing device manufacturers (smartphones, tablets, connected objects, etc.) to equip their products with LIFI as standard. Without the critical size effect of the terminal fleet equipped with LIFI-compatible interfaces, this technology could remain confined to very professional industrial universes or very targeted market "niches" as is the case for CPL (Courant Porteur en Ligne) which in the early 2000s was positioned as a competitor to ADSL for home internet access. However, its market has been reduced to the small portion of "internal distribution" to buildings, particularly housing, in support of or in addition to WIFI. PLC could find a new lease of life with the widespread adoption of smart electricity meters as part of the "smart grid" evolution (in France, in particular, 35 million Linky meters will be equipped with PLC within 10 years). The future of Li-Fi is therefore uncertain, but it is a complementary technology to existing ones.

What has made Wi-Fi so successful is, above all, its adoption by device manufacturers around the world and the production of chipsets integrating Wi-Fi at a very low cost. This is certainly the major challenge facing this new wireless technology!

To address this and other challenges, the Li-Fi promoters have formed the Li-Fi Consortium.

Li-Fi Consortium to promote this innovation

The founding members of the Li-Fi Consortium are international technology companies and research institutions specializing in optical communications technologies.

The group is based on a collectively developed concept and roadmap to bring a new wireless technology to market that surpasses the capabilities and qualities of Wi-Fi.

The Li-Fi Consortium has several objectives:

• Promote the state-of-the-art of optical wireless communication technologies and solutions to financial investors, public institutions, and the general public;
• Inform interested stakeholders to develop and finance the technology;
• Create and develop complete solutions and applications in anticipation of customer needs;
• Coordinate with standards groups and other industry organizations to provide OEM customers with a comprehensive technical and marketing suite.

A representative from each of the Li-Fi Consortium's founding members constitutes the Steering Committee. Their role is to develop and manage the scope and direction of technologies, applications, and relationships to fulfill the Consortium's mission.

The Steering Committee currently consists of representatives from the five founding members:

• Fraunhofer IMPS, Germany – Frank Deicke
• IBSENtelecom, Norway – Walter Kraus (Chair)
• Supreme Architecture, USA, Israel – Josef Shwartz
• TriLumina, USA – Rudi Wiedemann

The Li-Fi Consortium is encouraged to develop promotional materials and tools, including a website, white papers, links, press releases, articles, etc., that will serve as its official mission statement.

A key function of the Li-Fi Consortium is to establish and maintain working relationships with other organizations that can help create an environment of industry maturity for their implementation.

October 2013, China enters the LIFI battle!

In October and November 2013, according to China's Xinhua news agency, scientist Ms.Chi Nan of Fudan University Shanghai conducted an experiment and presented a LIFI pilot at the China International Industry Fair in Shanghai (5-9 November 2013). Tested data connection speeds reach 150 Mbps using a small number of LED bulbs, each one watt. "With a more powerful LED bulb, we can achieve speeds of 3.5 Gbps." Both the router and the receiver are equipped with LED bulbs to enable data transmission and reception.

According to Professor Chi Nan, "There are still many problems that need to be solved," emphasizing the need to improve Li-Fi coverage and miniaturize the necessary components. Over time, however, the Li-Fi receiver could eventually take the form of a "USB dongle" that attaches to a laptop. Chi Nan estimates it will take five years for the technology to reach the consumer market. So far, his team has spent about 18 months on the project.

December 2013, Li-Fi research update in the UK: EPSRC's Ultra-parallel visible light communications (UP-VLC) project

Latest concrete advances in Li-Fi by researchers from the universities of Oxford, Cambridge, St Andrews, Strathclyde, and the University of Edinburgh (source article) and the research site (EPSRS site).

Li-Fi as an alternative to Wi-Fi? These researchers are convinced of this, having succeeded in achieving wireless speeds exceeding 10 Gbps: 250 times faster than the maximum speeds available in homes. To achieve this, they chose to use light waves rather than radio waves, which are the basis for Wi-Fi.

Several research projects already exist in this field, using continuous or discontinuous light. One of the main parameters influencing the data rates achieved is the switching frequency of the light source used.

LEDs and lasers are among the sources with the highest switching frequencies, enabling the best data transfer performance in the field, but posing a real challenge in terms of stability in the communication protocol between the transmitter and receiver.

Latest concrete advances in LIFI by researchers from the universities of Oxford, Cambridge, St Andrews, Strathclyde, and the University of Edinburgh (source article) and the research site (EPSRS site).

This is precisely the challenge that the research activities of the Ultra Parallel Visible Light Communications project, jointly managed by the universities of Oxford, Cambridge, St Andrews, and Strathclyde, and funded by the Engineering and Physical Sciences Research Council (EPSRC), have recently overcome.

Each LED used in these conditions is capable of generating a flow rate greater than 3 Gbps, so the researchers managed to couple 3 different LEDs and make them operate simultaneously to achieve the colossal flow rate of 10 Gbps.

Some links in English about Li-Fi:

TECH RADAR, 11/28/13: Li-Fi researchers smash through 10Gbit/s data barrier using LED light bulbs.

THE INDEPENDENT: 11/28/13, Li-Fi revolution: Internet connections using light bulbs are 250 times faster than broadband.

January 2014, First Li-Fi-equipped smartphone presented at CES in Las Vegas by the French company SunPartner:

The French company SunPartner presents Wisyps Connect, a Li-Fi-compatible coating. The idea is simple: the coating is capable of capturing light to transmit data to the smartphone, but also—SunPartner's specialty—charging the device. Wysips Crystal is a photovoltaic coating capable of transforming light into energy usable by the phone.

This is not a finished product but a prototype, as SunPartner is using a mid-range smartphone already on the market to demonstrate Wysips® Connect. This presentation is intended to attract mobile phone operators and convince them to switch to Li-Fi.

The company reports having signed with three manufacturers to offer Li-Fi-compatible smartphones starting this year, 2014, including the Chinese manufacturer TCL, which offers smartphones under the Alcatel One Touch brand. Li-Fi integration is currently complementary to Wi-Fi or 4G.

Since early 2016, rumors have suggested Apple plans to install Li-Fi in its smartphones. Initially, a line of code in "IOS 9.1" allegedly referred to "Li-Fi Capability." However, imagining the Cupertino company's next smartphone with Li-Fi is a huge leap forward. This transition to typical consumer devices represents a significant market challenge for Li-Fi technology. Without this transition, it could be limited to professional applications for many years, or even never reach this milestone.

OLEDCOMM French Startup Presents Li-Fi in Las Vegas

Below, watch the video of OLEDCOMM's Li-Fi presentation.

At the end of 2015, a number of pilot sites, particularly in France and Europe, were launched:

Sogeprom, a subsidiary of Société Générale, kindly agreed to serve as a guinea pig, and a prototype Li-Fi lighting fixture was installed in its offices at La Défense.

Perpignan Hospital is the first healthcare facility to have tested Li-Fi in an Emergency Department. The network provides access to patient records.

Since 2012, SNCF has been studying the possibility of using the reading light above each seat in SNCF trains to transmit information to passengers via a Li-Fi signal: regions visited, arrival times, traffic disruptions, etc.

Installed on street lamps, Li-Fi transforms public lighting into "smart lighting." Only one city in France has launched a public Li-Fi network: the small town of Meyrargues, in the PACA region, which has fewer than 4,000 inhabitants. In train stations, Li-Fi could be used as a GPS beacon to assist the visually impaired.

All these initial applications show that Li-Fi is positioned more as a complement to Wi-Fi than as a substitute. It is currently coupled with Wi-Fi or Bluetooth to ensure the "upstream" (from the user terminal to the network).

However, the first attempts at "upload" have been appearing since 2015.

Towards "bidirectional" Li-Fi?

A manufacturer (Pure Li-Fi) with a "Li-1st" offering, however, does not offer the same performance: approximately 11.5 Mbps for the combined upload/download speed. This translates to 5 Mbps for the useful upload and 5 Mbps for the download.

First Bidirectional Li-Fi Experiment by LUCIBEL in FRANCE: 2016 (source RT Flash)

A prototype of a bidirectional, high-speed lighting fixture, or Li-Fi, developed by the French company Lucibel, was tested at the headquarters of the real estate developer Sogreprom in La Défense.

For Lucibel's Li-Fi project director (Edouard Lebrun), "This is a first in Europe. Until now, the proposed solutions were unidirectional with a downstream flow." SNCF and the Louvre have tested solutions of this type. Lucibel aims to offer an alternative to Wi-Fi.

For the moment, the tested solution achieves a downstream speed of 10 Mbps and an upstream speed of between 5 and 10 Mbps, depending on the status of the local network. The luminaire must be connected to the local Ethernet network.