Everyone knows about Wi-Fi, but have you heard of Li-Fi? Light Fidelity, or Li-Fi is a new technology set to revolutionise data transfer.
Li-Fi is a Visible Light Communications (VLC) system. Like Wi-Fi it’s a bidirectional wireless communication technology. But, where Wi-Fi uses radio waves to transmit data, Li-Fi uses visible light from LED lightbulbs fitted with a special chip.
Li-Fi can compensate as the radio spectrum becomes overloaded. Using the visible light spectrum, Li-Fi technology can transmit data and unlock capacity, which is 10,000 times greater than that available within the radio spectrum.
The visible light spectrum is plentiful, free and unlicensed, mitigating the radio frequency spectrum crunch effect.
Li-Fi technology will in future enable faster, more reliable internet connections, even when the demand for data usage has outgrown the available supply from existing technologies such as 4G, LTE and Wi-Fi. It will not replace these technologies, but will work seamlessly alongside them.
Using light to deliver wireless internet will also allow connectivity in environments that do not currently readily support Wi-Fi, such as aircraft cabins, hospitals and hazardous environments.
Light is already used for data transmission in fibre-optic cables and for point to point links, but Li-Fi is a special and novel combination of technologies that allow it to be universally adopted for mobile ultra high speed internet communications.
The wide use of solid state lighting offers an opportunity for efficient dual use lighting and communication systems.
Innovation in LED and photon receiver technology has ensured the availability of suitable light transmitters and detectors, while advances in the modulation of communication signals for these types of components has been advanced through signal processing techniques, such as multiple-input-multiple-output (MIMO), to become as sophisticated as those used in mobile telecommunications.
Data is transmitted over Li-Fi by modulating the intensity of a light- essentially dimming the light or turning it on and off at a very high speed (see above). The changes are so fast that they’re imperceptible to the human eye, so it isn’t intrusive.
This light is then received by a photo-sensitive detector and demodulated in electronic form. It’s then converted back into a data stream, making it usable for video, audio and other internet tasks.
The benefits of Li-Fi emerge as a result of unlocking the vast amounts of license-free and secure electromagnetic spectrum that lies in the infrared and visible light regions. The main benefits are:
What are the disadvantages?
The main downside to Li-Fi is that it can’t travel through walls, so it’s inevitably going to be a very short range technology. However, while it can’t travel through walls it can bounce off them and therefore go around corners.
Another limitation of the technology is that the Li-Fi LEDs need to be kept on in order to transmit data, although this could be at a dimmed rate lower than human visibility.
Commercial products are already on the market and proving popular, even though the data transfer rates aren’t close to the theoretical potential and they are aimed at the business market rather than consumers. Due to its limitations (primarily the fact that it can’t pass through walls), Li-Fi is never likely to replace Wi-Fi, 4G or 5G, but it could become a key complementary technology, handling data in areas where its limitations aren’t a problem and lessening the load on radio frequency spectrum in the process. Global Market Insights forecasts that the Li-Fi market will be worth £58.8 billion by 2023 indicating the huge potential of the technology.