Connecting to the Internet via Wi-Fi? Do you like speed? Don't you want it faster?

Professor Harald Haas invented Li-Fi - a technology for “super-speed” information transmission that allows you to distribute the Internet through... a light bulb.

What's happenedLi— Fi Internet

Technically, this is implemented using a chip built into LED lamp– such a “light bulb” is capable of transmitting data a hundred times faster than modems using traditional technologies.

Sounds like news from the distant future? However, this is already a reality - devices running on Haas technology are already on the market.

→ Beginners, read —

What is li-fi anyway??

This is a high-speed data transmission technology that uses light in the visible spectrum as a “carrier”. During transmission, the LEDs flash, turning off and on for very short periods. The blinking frequency is so high that it is impossible for the human eye to notice the flickering, which makes it possible to use lamps with such LEDs for lighting.

What li-fi is in reality was tested by the Estonian company Velmenni. Its employees installed appropriate equipment in several production facilities and offices in Tallinn and measured the transmission speed. The result was amazing: information was transmitted via li-fi at a speed of 1 gigabit per second! For comparison, in most wi-fi networks the average transmission speed does not exceed 10 megabits per second.

I will not rush to say that this new technology is the future. Most likely, the emergence of li-fi will not cause the disappearance of Wi-Fi - these methods of transmitting information will coexist peacefully for a long time. WiFi equipment will be installed where justified and possible. And devices such as laptops, smartphones and similar gadgets will acquire an option that allows you to “seamlessly” switch between “old” 3G networks, Wi-Fi and the “newest” light Internet.

Deepak Solanki, general manager Velmenni predicts widespread adoption of the “lamp” method of data transmission in the coming years. In the meantime, engineers are thinking about how to take advantage of the technology for those users who want to work on devices connected to the Internet not only with the lamps on, but also in complete darkness.

Professor Haas told the scientific world about what li-fi is five years ago. By that time, he had been developing the “light Internet” for about ten years. By the way, scientific name This technology is visual light communication (abbreviated as VLC).

→ Have you seen this? —

In 2011, Harald Haas demonstrated how an LED lamp equipped with a special chip transmits HD (high-definition) video to a computer. By that time, the scientist had come up with a more sonorous name for the technology, renaming VLC to li-fi (short for light fidelity).

Given the cost, availability and ubiquity of LEDs, li-fi communications promise to be a more energy-efficient and cheaper solution than wireless radio systems used today.

That part of the electromagnetic spectrum, which is visible light, is 10 thousand times wider than the radio spectrum. The potential width of the “light” transmission channel is almost unlimited. The advantages of li-fi, according to Haas, include a more stable and accurate connection of computers to networks inside buildings - the main thing is to evenly distribute the LED transmitters. This is especially important against the backdrop of a strong weakening of the signal of a regular wi-fi router as you move away from the modem (because of this, in offices and residential buildings zones appear with such weak connections that it becomes impossible to connect to the Internet in them).

What is lifi from a security point of view?

Visible light cannot pass through walls. This property, Professor Haas believes, makes VLC technology more reliable in matters of confidentiality of transmitted information than the popular wi-fi today.

What is Li-Fi

A wireless technology that works like Wi-Fi, but is many times faster and uses visible light rather than radio waves. IN laboratory conditions via Li-Fi they were able to transmit data at a speed of 224 Gbit/s, which is 22.4 times faster maximum speed the developing IEEE 802.11ax Wi-Fi standard, 30 times faster than IEEE 802.11ac (it is used, for example, in the 2015 MacBook Pro).

What does this speed allow?

In 1 second, you can download approximately 20 HD movies, an archive of 50,000 photographs, or as much text as a book depository with an area of ​​approximately 2000 square meters contains. m.

How does this work

The role of the router is played by an LED light bulb (sometimes three: red, green and blue), flickering so quickly that the human eye sees a uniform luminous flux. The flicker transmitting information is received by a photodetector, which decrypts the information. This is how the laptop gains access to the Internet. High speed Li-Fi is obtained for several reasons: short wavelength, high density signal and a wide transmission channel (the frequency spectrum of visible light is much wider than the spectrum of radio waves).

Why Li-Fi is worse than Wi-Fi

Li-Fi is not the most reliable connection. It works well within the room and at a distance of about 10 meters, but the router will not be able to transmit the signal to another room (oddly enough, the light does not pass through the walls). Li-Fi does not require line-of-sight operation. If you place a table between the router and the detector, then Internet access will not disappear: the light will be reflected from the walls and reach the detector, but the speed will drop to 70 Mbit/s. On outdoors the router will only work at dusk or in heavy clouds - and then at a very short distance. In bright sunlight, as with other artificial sources, or, for example, in the case of fog, the router will not be able to transmit data. Wi-Fi has no problems with this.

Why is it better than Wi-Fi?

The most important thing is that it is much faster than connections through regular Wi-Fi routers, and in theory the speed can be increased many times over. Li-Fi is difficult to hack because the signal does not leave the room. The router does not need to waste energy on heating (as is the case with Wi-Fi), so it will work economically. Since the transmission of light remains free, companies will not have to pay for radio frequency licensing.

Where can you use Li-Fi

Developers and journalists have come up with three areas where the Internet will begin to be distributed through light bulbs in the near future. Firstly, on airplanes. Wi-Fi interferes with aircraft instruments and communications, and excess cables add to the weight of the aircraft. Li-Fi looks like an ideal solution: its signal will not go beyond the passenger compartment, and the equipment weighs almost nothing. Secondly, Li-Fi can be used in banks and organizations that value secrecy. In this case, the disadvantage of a Li-Fi router (distributed only within the room) will become an additional security barrier: attackers outside the room will not be able to intercept the signal, and it will be easier to control leaks inside it. Thirdly, industry, heavy data processing and production, where a large amount of data needs to be transferred quickly.

Where is it being used right now?

So far, the system is only being tested, but at the end of last year, the Estonian startup Velmenni installed a Li-Fi network through which data was transmitted at a speed of 1 Gbit/s (for comparison: the fastest Rostelecom tariff in Moscow is 100 Mbit/s). It turned out to be difficult to completely switch to Li-Fi, so Velmenni used a combined network: Wi-Fi and Li-Fi.

Who invented this technology

The principle of operation of Li-Fi was first formulated by 46-year-old German physicist and professor at the University of Edinburgh Harald Haas. Since 2007, he and his students have experimented with transmitting data through LED light bulb from IKEA, and in 2011, Haas spoke about his vision of the future at a TED conference. The professor founded the company PureLiFi, which conducts research and sometimes produces LED routers. Haas's idea was not fundamentally new - in 1880, Alexander Bell tried to transmit sound using a light signal to a device called a photophone. Haas simply derived Bell's experiments from new level and decided to transmit not sound, but information.

Why Li-Fi is needed in the future

Wi-Fi will not cope with the Internet of things, says Haas. By 2020, there will be 20.8 billion wearable devices and smart home appliances in the world, almost three for every person. If they start transmitting data via Wi-Fi in the same frequency range, interference will begin to impede transmission. Today, such a drop in speed can be observed in busy places with many working routers. And by 2025–2030 the situation will become more complicated. Haas envisions a world where the Internet can be heard from every light bulb (they need to be modified to do this), videos can be downloaded from a street lamp, and cars communicate with each other through the light of their headlights.

Does Li-Fi belong to one organization?

No, he does research, promotes the idea among manufacturers and obtains funding. But there are other companies: in 2014, they were able to transmit data via light at a speed of 1.25 Gbit/s, Sisoft - at a speed of . Recently, NASA and Apple became interested in Li-Fi (iOS 9.1 code supports light transmission).

When Wi-Fi will end

Most likely not soon (at least in the near future). Even the developers of light transmission admit this. In three to four years, when the first LED routers appear on consumer market, will use a combination of Li-Fi and Wi-Fi networks. But the latter will continue to exist, since Li-Fi still has unresolved problems (outdoor transmission).

Light Fidelity - Li-Fi technology in short - is an optical technology for wireless information transmission. The technology was developed and presented quite recently - in 2011. This happened at a TED Talk. The developer is scientist Harald Haas. The data transfer speed was then about 10 Mb/s. The scientist promised that by the end of 2011 it will be 100 Mb/s.

How does Light Fidelity technology work?

The essence of the technology is modulation of the light flow from a special LED source using a binary code. Human eye is not able to catch this process, since the modulation process occurs on high frequency. This type of optical communication is much more secure than the traditional Wi-Fi that we are all used to. Why? Let us remind you that Wi-Fi signals can be intercepted from almost any point that is within the range of the equipment. But in order for some bad citizen to be able to intercept information transmitted via Li-Fi, it is necessary to place his equipment almost “on the lap” of the owner of the Li-Fi. It is clear that this is impossible.

There is another serious argument in favor of Li-Fi technology. It can be used with virtually no restrictions in areas where there is a ban on the use of equipment that emits extraneous radio waves. It’s no secret that such waves often violate normal functioning critical equipment. As an example, we can cite the chambers intensive care medical institutions, where there is a lot of different medical equipment, airplane cabins and so on.

A little bit of history

Many readers probably remember that the idea of ​​using light to transmit data is not new. Do you remember how back in school, during physics lessons, we were told about Alexander Bell? In 1880, Alexander Bell managed to send a message using a photophone.

Here in recent years Developers began to become interested in visible light communications. Scientists realized that the proliferation of LEDs, which can be more finely tuned than conventional incandescent lamps, would certainly make the technology more economical and easier to use. One more thing should be noted important factor- the exponentially growing popularity of wireless communication devices around the world, which should inevitably lead to a shortage of radio frequency spectrum. This gave rise to the need to look for an effective alternative.

Why was it necessary to create Li-Fi technology?

The question of the need to use wireless information transmission is not currently raised at all. We live in the age of information networks. Some ten to fifteen years ago there was no mass access to the Internet; now literally every home has its own local network transfer of information.

But almost everything developed and used in at the moment Data transmission technologies have, in addition to their advantages, serious disadvantages. We are not talking about wired connections at all, since their use is justified in cases where there is too great a distance or a stationary computer. In this case, it is enough to get the wiring once and get an acceptable result in the future. But at the same time, it is necessary to use a certified cable; in addition, you need to have knowledge basic principles laying cables and have skills in crimping ends.

Nowadays, wireless networks based on Wi-Fi technology are used in almost every home. There are hybrid networks that combine wired and wireless channels. What is the inconvenience of wireless Wi-Fi networks? The first is the question of the security of the wireless communication channel, which arises quite often. It is not uncommon to hear assurances from network device manufacturers who claim that hacking a wireless network is impossible. But these assurances raise serious doubts. Secondly, no one can guarantee that long action On the human body, exposure to electromagnetic waves in the operating ranges of wireless adapters is completely harmless. Not too much yet long period humanity uses this technology, so it is impossible to draw an unambiguous conclusion. The radiation power is not too high, but there is a high prevalence and duration of exposure. Who knows what results await us in a few decades, and maybe even earlier.

What does Li-Fi technology provide?

Light Fidelity can eliminate all these disadvantages. Since, as we have already said, this technology uses visible light coming from any LED source to transmit data, this way you can maintain mobility without harm to the human body. Internet speed increases to several gigabytes, and the network coverage area expands significantly.

Since the principle of Li-Fi technology is that absolutely any LED lighting bulb is capable of “blinking” at an incredibly high speed, this allows the use of light modulation to transmit information. Look at this ingenious solution: in a home network, even an ordinary table lamp can be an information transmitter! Ceiling lighting fixtures and decorative lighting elements - whatever! Having a mobile gadget, you can easily move around the apartment, since we are always connected to the network!

But it is worth noting that things are much more complicated with the reverse transfer of data from the device to the network. In such cases, it becomes necessary to think through the successful placement of sensors on the walls and ceilings of the premises.

Additional equipment for Li-Fi technology is almost not needed, because you can use what has already been used for a long time: street lamps, car headlights, room lighting. For example, the well-known manufacturer of audio speakers Klipsch presented a prototype back in 2010 that can receive music data from ordinary household LED lamps.

Li-Fi technology - prospects

There is no doubt that the promise of Li-Fi technology is enormous. If you use your imagination, an alley in some city equipped with LED emitters will become an opportunity for free broadband access on the Internet for everyone.

Interestingly, Li-Fi sensors and emitters can be installed everywhere: they can be placed on street lighting poles, on trees, on the walls of buildings. At the same time, absolutely any device that is nearby also gains access to the network. In addition, it is possible to replace the traditional cellular communication we are accustomed to with a hybrid one, for example, using Li-Fi in working conditions in a large metropolis and radio waves outside the Li-Fi access zone. It is clear that considerable costs will await us here. But very soon such investments will pay off.

Are there any disadvantages to Li-Fi technology?

Perhaps the only drawback of Li-Fi technology is the need for direct visibility between the light source and the receiver.

And in conclusion, we can say: if Light Fidelity technology becomes widespread, then the electrician profession will become the most in demand and respected. This is, of course, a joke. But seriously, Li-Fi technology undoubtedly has a great future.

Thank you for your attention to our site, if you liked the published information, you can help in the development of the resource by sharing the article via social networks.

Image caption Wireless optical data transmission technology will allow you to connect to the Internet at enormous speeds

British scientists claim to have achieved data transfer speeds of 10 Gbit per second using new technology"li-fi" - wireless communication through light.

The researchers used a micro-LED lamp, transmitting 3.5 Gbits of information per second through each of the three "primary" colors - red, green and blue - that together make up ordinary "white" light.

This means that by adding up the channels, you can transfer data at a total speed of 10 Gbit per second.

"Li-fi" is a new technology (the abbreviation in the name is made, by analogy with the well-known Hi-fi and Wi-fi, from English words"light" - "light" and "fidelity" - "accuracy"), promising a reliable and cheap way to connect to the Internet from almost anywhere using special LEDs.

High speed

The project to study data transmission using so-called ultra-parallel visible light was initiated by the Universities of Edinburgh, Oxford and Cambridge and is funded by British Council in Research in Engineering and Physical Sciences.

Tiny microLEDs, developed at the University of Strathclyde in Glasgow, emit parallel streams of light, thereby multiplying the amount of data that can be transmitted per unit of time.

“Imagine a shower head that directs water in strictly parallel streams - and we made light behave in the same way,” explains Professor Harald Haas, an expert in optical wireless transmission at the University of Edinburgh and one of the initiators of the project.

A digital modulation technique called orthogonal frequency division division (OFDM) allowed scientists to use microLEDs to transmit millions of beams of light of varying intensities per second. To put it simply, the lamps turn on and off - but at breakneck speed.

These on-off switches create huge amounts of binary data, chains of ones and zeros, transmitted at high speed.

Earlier this year, German scientists from the Fraunhofer Heinrich Hertz Institute claimed that they were able to achieve data transfer speeds using LEDs of 1 Gbit per second in laboratory conditions.

In October, Chinese researchers reported that they had built an LED on a microchip with a speed of 150 Mbps, providing an Internet connection to four computers at once.

"Light quality"

Professor Harald Haas has been developing li-fi for ten years. In scientific language, this technology is called "visible light communication", or VLC for short ("visual light communication").

In 2011, Haas demonstrated that an LED lamp equipped with signal processing technology could transmit "high-definition" video images to a computer.

He also came up with a more sonorous name for the VLC technology - “light fidelity” or simply “li-fi”.

"Li-fi" promises to be a cheaper and more energy-efficient method of data transmission than existing wireless radio systems, given the availability and ubiquity of LEDs.

Visible light is part of the electromagnetic spectrum, 10 thousand times wider than the radio spectrum. Potentially, light can provide virtually unlimited data transmission channel width.

According to Professor Haas, another advantage of the new technology is that by evenly distributing LED transmitters, much more accurate and stable internet connections can be achieved inside buildings.

The disadvantage of traditional Wi-Fi routers has always been that the signal weakens as you move away from the transmitter, and in homes and offices there are areas where the connection is so weak that the Internet connection becomes unstable or is completely interrupted.

In addition, visible light does not pass through walls, so VLC technology is potentially more secure than traditional Wi-Fi in terms of maintaining the confidentiality of data transmission, Professor Haas points out.

What is Li-Fi

Li-Fi (Light Fidelity) is a fairly young technology. Its founder is considered to be the German physicist Harald Haas, who in 2011 used an LED lamp as a router. In laboratory conditions, it reached a transfer speed of 224 Gb/s. This speed allows, for example, to download 18 1.5 GB movies or up to 50,000 photos in one second! The idea was made possible thanks to VLC (Visible Light Communication) technology, which allows the light source not only to perform the lighting function, but also to transmit information. Data transit is realized by LEDs, the nanosecond flickering of which is imperceptible to humans.

Benefits of Li-Fi technology

The advantage of Light Fidelity is high speed data transfer. If we take 224 Gb/s as a basis, then Li-Fi exceeds the maximum speed Wi-Fi standard IEEE 802.11ax is 22.4 times, and IEEE 802.11ac is 30 times.

The second advantage of the technology is its relatively high security against hacker penetration. The fact is that the light underlying the transmission does not pass through the walls. Therefore, to hack a Li-Fi network, an attacker must be in close proximity to the signal source, thereby losing his anonymity.

Disadvantages of Li-Fi technology

The above plus follows from the main disadvantage of Light Fidelity technology, namely the short range of information transmission. Not only does the hacker have to be close to the light source to carry out the hack. The user himself can use Li-Fi only within the premises.

Comparative analysis of Li-Fi and Wi-Fi technologies

Li-Fi and Wi-Fi technologies are based on similar IEEE 802.11 protocols. However, Li-Fi uses electromagnetic waves visible light, while Wi-Fi uses radio waves. Thanks to this, the first technology gains an advantage in terms of wider bandwidth.

The IEEE 802.15.7 standard defines for Li-Fi the physical layer of the OSI PHY (Physical layer) network model, as well as the MAC address control layer (Media Access Control). The working version of IEEE 802.15.7 distinguishes three PHYs, different in throughput, which are presented in table 1.

Table 1 – Characteristics of the physical layers of the Li-Fi standard (IEEE 802.15.7)

Compared to Wi-Fi, Light Fidelity has a significantly faster O higher data transfer speed. However, the technology is capable of propagating a signal over significantly shorter distances than radio waves.

Thus, Li-Fi technology compared to Wi-Fi:

1. Uses visible light waves instead of radio waves.

2. Has a wider bandwidth.

3. Has b O higher data transfer speed.

4. More information-safe.

5. Has a smaller coverage area.

6. Helps optimize energy costs by combining the lighting system and hot spots.

7. Li-Fi devices do not interfere with each other on the network.

Li-Fi technology as a revolution in wireless data transmission

The pioneer of lighting technology, Haas believes that the advantages of Li-Fi will make the lighting network relevant in the digital world. According to him, Wi-Fi will not be able to meet the mobile data requirements of Internet of Things concept. By 2020, for every user there will beapproximately three network devices. IN real indicators– order 20.8 billion connections. If all devices start using the same Wi-Fi frequencies, there will be interference on the network, which will negatively affect data transfer speeds. Over the second half of the third decade, the situation will only worsen. An effective solution may be, according to Haas, Light Fidelity technology, thanks to which any light bulb adapted for this function will distribute the signal.

Timeframe for implementation of Li-Fi technology

To date, there is no talk of commercial launch of Li-Fi. However, the higher the frequency of use of LED lamps, the more O Greater opportunities are opening up for the spread of light data transmission. Any LED can simultaneously illuminate a room and broadcast arrays of binary data. According to Grand View Research, the market for light data transmission technology will grow to $100 billion by 2024.

The main company involved in the research, development and promotion of Li-Fi is PureLiF, founded by Harald Haas. However, other commercial structures are showing interest in the technology. For example, Li-Fi tests were carried out Beamcaster , reaching 1.25 Gbit/s, and Sisoft, which transmitted data at a speed of 10 Gbit/s.

In the fall of 2016, information appeared that Lucibel, a company specializing in LED lighting, with which PureLiF collaborates, was ready to implement a project to equip the world’s first office with two-way data transfer using Li-Fi technology. The solution is planned to be implemented in Paris.

Another French company, Oledcomm, according to the received tender, must equip over 60 stations of the Paris metro with 250 thousand LED light sources. In this project, Li-Fi technology will use one-way communication. For example, transmit information about the location of objects.

Also in the code operating system iOS Apple Found information on testing data transmission using Li-Fi light radiation.

Will Li-Fi replace the Wi-Fi standard?

Most likely, Wi-Fi will not be completely replaced by Light Fidelity technology. Li-Fi developers assume that the product will reach the mass market no earlier than in 3-4 years. LED routers will be used in combination with Wi-Fi. This is due to the presence of unsolved problems in light data transmission technology.

In particular, Li-Fi is difficult to use outdoors, so this area can be served by Wi-Fi. If Harald Haas’s vision comes true and any light bulb can produce a signal, then you shouldn’t expect this in the near future. The most likely scenario is the combined use of Li-Fi and Wi-Fi.

With technical features of the functioning of mobile communication networks in licensed and unlicensed frequency ranges(technologies HetNet, LWA, LAA, eLAA, Multefire and others) can be found in the book "