Li-Fi is a new data transfer technology that will radically change the business in the future, create opportunities that are ripe for use today, and is preparing to become a multi-billion dollar industry by 2022. Currently, work is underway to achieve a speed of 1 Gbit / s, which will exceed the performance of ultrafast broadband access.
Information light
The term Li-Fi was coined by Professor Harald Haas and refers to a method of transmitting information using light, which provides high-speed bi-directional mobile communications such as Wi-Fi. It can be used both for unloading existing networks operating on radio frequencies, and for increasing their throughput.
For ultrafast communication, the visible part of the electromagnetic spectrum is used. This distinguishes this technology from an established form of wireless communication such as Wi-Fi, in which traditional frequencies are involved.
In Li-Fi, data is transmitted by modulating the light intensity, received by a photodetector, and the signal is converted into electrical signal. Modulation is performed in such a way that the human eye does not perceive it.
The technology of high-speed optical communication Li-Fi belongs to the category of wireless communications, which, in addition to visible light, includes infrared and ultraviolet. Its uniqueness lies in the use of existing lighting networks.
Li Fi - Ultra-fast Internet with LEDs
When direct current is supplied to the LED lamp, it emits a stable photon flux of visible light. With a decrease or increase in current, the brightness of the glow also changes. Since LED lamps are semiconductor devices, the current and therefore the optical output can be modulated at a very high speed. It can be taken by a photocell and converted back into electric current. The brightness modulation is invisible to the human eye and is as convenient as the radio. Using this technique, an LED lamp is capable of transmitting information at high speed.
RF communication requires an electrical circuit, antennas and sophisticated receivers, while Li-Fi technology is much simpler. It uses direct modulation methods, similar to those used in low-cost infrared communication devices - remote controls. The use of infrared communication is limited due to the requirements of sanitary eye safety standards, while LED lamps have a high luminous intensity and demonstrate a significant speed.
Light or radio?
Li-Fi can turn the lamp into a wireless access point, similar to a Wi-Fi router.
In traditional communications, radio frequencies are used, but their number is very limited. Devices - computers, laptops, printers, smart TVs, smartphones and tablets - must compete for bandwidth. The advent of an increasing number of things using Wi-Fi, such as refrigerators, watches, cameras, cell phones, is causing delays and lower data transfer speeds. Li-Fi technology uses frequencies of light waves, which are 10,000 times more than radio frequencies.
Radio waves create electromagnetic interference, which interfere with the operation of instruments and equipment of aircraft, hospitals and are potentially dangerous in industries such as nuclear energy, drilling oil and gas wells. Li-Fi uses intrinsically safe light and does not cause electromagnetic interference.
Radio waves pass through walls and ceilings. The light does not. This is the difference in data protection between Wi-Fi and Li-Fi. A hacker located outside the building is able to connect to the radio network inside it. Data transmitted via Li-Fi is available only where the lamp shines.
The Wi-Fi standard 802.11a / g provides a transfer rate of up to 54 Mb / s, and this value can be increased to 1 Gbit / s. The University of Edinburgh has already reached 3 Gb / s in monochrome. One full-color RGB LED can transmit up to 9 Gb / s.
Internet from a Li-Fi light bulb
The development of this technology was facilitated by the sharp increase in the use of LEDs for lighting purposes.
Li-Fi is the best suited for downloading video and audio, live broadcasts, etc. These tasks impose high demands on the bandwidth of the input channels, but require minimal outgoing power. Thus, most of the Internet traffic of existing radio frequency channels is freed up, expanding the capabilities of cellular communications and Wi-Fi.
Light Internet Li-Fi is used in many areas:
- Radio Frequency Release: Peak loads on cellular networks can be shifted to Li-Fi. This is especially effective on input communication channels, where bottlenecks occur most frequently.
- Smart lighting: any private or public lighting, including streetlights, can be used as Li-Fi access points, with the same infrastructure of communications and sensors.
- Mobile connections: laptops, smartphones, tablets and other mobile devices can be directly connected via Li-Fi. The short distance provides excellent and secure communication.
- Hazardous production: Li-Fi technology provides a safe alternative to electromagnetic interference from radio frequency communications at facilities such as mines and petrochemical plants.
- Medicine and health protection: light does not create electromagnetic interference and therefore does not interfere with medical equipment, and is also not affected by MRI scanners.
- Aviation: Li-Fi can be used to reduce weight, reduce wiring lengths and increase flexibility in the placement of passenger compartment equipment, where LED lights are already installed. The on-board entertainment system is capable of being supported and interacting with passengers’s mobile devices.
- Communication under water: due to the strong absorption of the signal, the use of radio frequencies in water is impractical. Acoustic waves have a very low bandwidth and disturb marine animals. Li-Fi technology provides a short-range communications solution.
- Vehicles and transport: headlights, taillights, street lamps, signboards and traffic lights that use LED lamps are already being produced. This makes communication between cars and road infrastructure possible in safety and traffic management systems.
- High-precision, local information services, such as advertising and navigation, which allow you to receive information related to a specific place and time.
- Toys: LEDs are used in many toys, which can be used for low-cost communication between interactive toys.
Prototype for developers
Li-1st enables customers to quickly develop and test Li-Fi applications. The device supports full duplex communication with a bandwidth of 11.5 Mbit / s at a distance of up to 3 m, while providing adequate lighting on the desktop. The working distance depends only on the strength of the light source. The device offers a simple, secure wireless network connection, combined with LED lamps.
Li-1st was created as a base for pilot projects of Li-Fi developers.
First commercial product
Li-Flame was publicly demonstrated at the Mobile World Congress in Barcelona in March 2016. The device represents the next generation of the world's first high-speed wireless network based on visible light. Li-Flame technology supports significantly higher data density than the best Wi-Fi solutions, and its inherent security will eliminate unwanted intrusion. In addition, the combination of lighting with wireless communication significantly simplifies the infrastructure and reduces energy consumption.
Li-Flame provides:
- half-duplex communication 10 Mbit / s at a distance of up to 3 m with standard fixtures;
- full mobility (portable desktop unit with autonomous power supply) with high data transfer speed due to the dense installation of Li-Fi access points;
- secure wireless communication within the premises, which eliminates the risk of signal leakage;
- multi-user access points providing greater bandwidth for each user;
- secure wireless communication in environments where radio frequencies are undesirable or inaccessible;
- flexibility in the design of communication networks;
- expanding the range of wireless applications;
- savings on lighting and telecommunications equipment due to the use of a single infrastructure.
Ceiling block:
- Data and power are supplied through a standard Ethernet port.
- Easy installation.
- It is connected to the LED lamp, forming atto-cells.
- Multiple access
- Smooth transition between access points.
Desktop part:
- Connect to a client device via a USB port.
- 10 Mbps infrared uplink to the ceiling.
- The swivel head of the transceiver can be adjusted by the user.
- Battery powered and portable.
The fastest, smallest and most secure
LiFi-X is an evolution of the Li-Flame system. It allows you to deploy a full network and, unlike existing products, supports multiple access, roaming, full mobility, and is also easy to use. It differs from the previous version with full duplex communication at a speed of 40 Mbps in both outgoing and incoming directions, and full mobility provided by a portable USB-station.
LiFi-X Access Point:
- Supports power over PoE or PLC.
- Easy installation.
- Connection to LED-lamps for the formation of atto-cells.
- Multiple access
- Smooth switching between access points.
LiFi-X Station:
Literature
Books on Li-Fi technology, despite its novelty, are no longer rare, although for the most part they are not translated into Russian. Here are just a few of them:
- Arnon, Shlomi. Visible light communication. Cambridge, United Kingdom: Cambridge University Press, 2015. Print.
- Dimitrov, Svilen, and Harald Haas. Principles of LED light communications: towards networked Li-Fi. Cambridge: Cambridge University Press, 2015. Print.
- Ghassemlooy, Zabih, W Popoola, and S Rajbhandari. Optical wireless communications system and channel modeling with MATLAB. Boca Raton, FL: CRC Press, 2013. Print.
Books are available on the Amazon online store.