Imagine transferring data over your local wireless network at the speed of light. Light Fidelity or Li-Fi is a revolutionary innovation that made this possible. Data communication through optical fibers has now made data communication available at the speed of light over long distances. Light Fidelity has filled the gap for optical communications in the wireless arena and can replace Wi-Fi networks. An optical wireless data communications technology capable of data rates 100 times higher than Wi-Fi, Li-Fi brings the promise of highly secure Internet communication without any radio interference. Li-Fi is based on the IEEE IEEE 802.15.7 standard – similar to and compatible with the IEEE 802.11 Wi-Fi standard.
What is Li-Fi?
Light Fidelity (Li-Fi) is a visible light communication (VLC) technology. Unlike Wi-Fi, which uses radio frequencies for data communication, Li-Fi uses visible light and infrared light spectrum for data communication over the Internet. The transceiver is a light source that transmits data by varying the intensity of the light. The light source in the transceiver is an LED and the data is received by a photodetector. The modulated light intensity is decrypted by a microcontroller to regenerate digital data from light waves.
Li-Fi was first demonstrated by Professor Harald Haas in the TED Global talk in 2011. Because the technology uses visible and infrared light waves for data communication and modulates light intensity rather than frequency, Li-Fi is much more economical compared to Wi-Fi. -Fi. It offers a wider frequency band of 400 THz compared to 300 GHz for Wi-Fi, so you can connect multiple devices to a Li-Fi network without any data latency. Li-Fi promises to be highly secure as data could not be accessed in the absence of light. Li-Fi is capable of reaching up to 42.8 Gbit/s, while Wi-Fi has a maximum data rate of 300 Mbps. Although the network coverage of a Wi-Fi network is greater than that of Li-Fi, Li-Fi is better at operating in high-density environments. Li-Fi network coverage can still be adjusted, extended or limited simply by changing the light intensity. While a WiFi network requires repeaters and routers to extend range, Li-Fi networks can be extended by synchronizing simple light sources.
Li-Fi allows data transmission through any light source, such as an LED lamp, a lamppost or a television screen. The device works both as a light source and as an internet transceiver. Li-Fi will be most useful for public wireless networks, such as those on streets, hospitals, schools and airplanes. In a Li-Fi network, the receiver needs to be within range of the light source. You can think of Li-Fi like surfing the Internet under a lamp or lamppost, or in front of a television set. Although the visible light range is used in Li-Fi, the light is of low intensity, or infrared, and therefore remains invisible to the human eye.
How does Li-Fi work?
Li-Fi primarily uses the visible light spectrum range between red (400 THz) and violet (800 THz). The two main components in data transmission are an LED light and a photodetector. Li-Fi works by modulating the amplitude of light in a well-defined, uniform pattern. The LED light that acts as a transmitter flashes at a speed that takes less than a microsecond. When the LED is on, it is deciphered as logical '1', and when the LED is off, it is deciphered as logical '0'. Because the oscillation of a light source occurs in less than a microsecond, it remains imperceptible to human eyes. On the receiver side, the oscillation of light waves is detected by a photodetector, which decrypts the binary '1's and '0's by interpreting the LED switching time period. Therefore, Li-Fi operates on a very simple and straightforward principle. Digital data is encrypted into visible light waves by high-speed LED switching and decrypted by detecting the high-speed switching with the help of a highly sensitive photodetector.
Advantages of Li-Fi over Wi-Fi
Li-Fi is 100 times faster than WiFi. The data speed of a WiFi network varies between 11 and ~300 Mbps. Typical data speed on Li-Fi network is 10 to 20 Gbps. The data speed of a Li-Fi network can reach 224 Gbps. Li-Fi offers 100x data speed at a hardware cost 10 times less than a WiFi network. All that is needed to build a Li-Fi network is an LED, a photodetector and a microcontroller. Any light source can act as a data transmitter or transceiver, so a Li-Fi network can be extended infinitely and made available anywhere; it will be possible to connect unlimited devices to a Li-Fi network. It uses a 400 THz wide radio spectrum that is 10,000 times larger than the frequency band used by WiFi.
A big advantage of Li-Fi is that it works without any interruption. Visible light waves are not interrupted nor do they interfere with radio waves. This makes Li-Fi a highly suitable Internet transceiver for use on planes and ships. Since the light waves used by Li-Fi do not penetrate walls, there is no chance of intercepting Li-Fi signals and hacking end devices.
Disadvantages of Li-Fi
Li-Fi's dependence on the visible light spectrum imposes limitations on the use of this technology. Firstly, because Li-Fi is based on the modulation of light waves, the maximum range of a Li-Fi transceiver is limited to 10 meters. Outdoors, the data transmission speed of a Li-Fi network may be affected by sunlight and other visible light sources. Inside, network coverage is obviously limited, as visible light waves cannot penetrate through walls; Even opaque obstructions within a room can restrict network coverage. Li-Fi networks require a close line of sight between the LED source and the photodetector. This can compromise the practicality of Li-Fi in many situations.
Li-Fi Applications
Some of the practical applications of Li-Fi networks include underwater communication, military communication, virtual reality, augmented reality, connected cars, and wireless Internet networks in hospitals, schools, airplanes, ships, and retail stores. Since Li-Fi signals do not interfere with radio waves, it is best suited for high-speed Internet on planes and ships. The absence of electromagnetic interference also makes Li-Fi suitable for Internet connectivity in hospitals, where Wi-Fi signals can interfere with electronic signals from monitoring equipment.
Li-Fi is useful for Internet connectivity where electromagnetic interference is not acceptable. For example, Li-Fi can provide a secure network connection within a power plant. Li-Fi networks that utilize infrared spectrum can also be used for underwater wireless internet. Furthermore, the technology is capable of making Internet services unaffected by natural disasters, such as earthquakes and hurricanes, as it operates without routers, antennas, modems, signal repeaters and amplifiers.
Li-Fi can be used in car-to-car communication as well as IoT deployment in traffic management. It can be installed and used in connected cars and many smart city applications, as well as high-speed Internet for home and office automation.
Big challenges
Li-Fi is expected to have a market value of US$115 billion in 2022. As LED prices fall, Li-Fi is expected to be more profitable in the future. While this growth is encouraging, there are major challenges to face. The IEEE 802.15.7 standard on which Li-Fi is based is now considered obsolete. The standard strictly requires a review to maintain Li-Fi as an emerging technology. In fact, with the introduction of Optical – Orthogonal Frequency Division Multiplexing (O-OFDM), the entire VLC technology needs a restandardization.
Conclusion
Li-Fi is a promising and fascinating technology that has significant advantages over Wi-Fi in terms of data rate, connectivity, environmental density, security and reliability. It promises to provide uninterrupted high-speed internet indoors and a limited range outdoors. Finally, Li-Fi can be used in inaccessible locations or where radio interference is a major issue, resulting in no Internet access or only low-speed Internet access.