Does Adding 'Wi-Fi' to Light Bulbs Make the Speed Faster? [Reading Science]

An illustration explaining the ultra-high-speed wireless internet 'Li-Fi' used for lighting.
[Photo by pure LiFi]

[Asia Economy Reporter Kim Jong-hwa] As web surfing on mobile phones has become routine, wireless communication technology like Wi-Fi is now available anytime and anywhere. Recently, a technology called 'Li-Fi' that surpasses Wi-Fi has been developed. Have you heard of it?

'Li-Fi' is a compound word combining Light and Wi-Fi. It is an amazing technology where the internet connects when you turn on the light in your home or office. In other words, the light bulb acts as a Wi-Fi transmitter. While Wi-Fi is a communication technology using radio waves, Li-Fi uses visible light from LED semiconductors for communication.

Li-Fi was first introduced in a 2011 lecture by Professor Harald Haas at the University of Edinburgh in the UK and has been spotlighted as the next-generation wireless communication technology to replace Wi-Fi. It was accidentally developed during research on adjusting the brightness of LED bulbs. Unlike general lighting, LEDs are semiconductor-based light sources that flicker so fast they are invisible to the naked eye. This characteristic was utilized for communication technology.

Li-Fi uses light bulbs as basic routers. Flickering visible light executes ultra-high-speed wireless communication. It is said that even with commonly used LED bulbs in households, data can be transmitted at speeds up to 222Gb per second.

Digital data uses binary code, a combination of 0s and 1s, to represent information. Li-Fi implements binary code through light flickering: light on represents 1, and light off represents 0, transmitting information over long distances.

The Li-Fi transceiver sensor installed in mobile phones or computers decodes this information into digital data and then converts it into electrical signals. The flickering speed of the light is over 200 times per second, so it is too fast for the human eye to perceive.

The biggest difference is that Wi-Fi uses radio waves, while Li-Fi uses the wavelength of visible light. Radio waves are public resources with limited usable frequencies, so mobile communication operators (ultimately consumers) pay fees for radio wave usage for a certain period. Also, since Wi-Fi uses shared frequencies, quality drastically drops when many users connect simultaneously due to interference.

On the other hand, the visible light frequency range used by Li-Fi does not require usage permission. It is a globally common frequency, over 10,000 times wider than the frequency range used by radio waves, and can send multiple data streams simultaneously, resulting in very high speeds. The maximum speed reaches 10Gbps, which is 100 times faster than Wi-Fi and about 66 times faster than wireless LTE-A.

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Although there are controversies about Wi-Fi’s electromagnetic waves and infrared being harmful to the human body, Li-Fi’s visible light spectrum is naturally widespread and always perceived by the eyes, making it safe. It also has advantages such as low installation costs, low power consumption, and a lower risk of hacking.

Professor Harold Haas of the University of Edinburgh, UK, demonstrating Li-Fi in a lecture in 2015.
[Photo by YouTube screenshot]

By simply installing a communication module on existing LED bulbs, Li-Fi can be immediately activated, making installation costs low and power consumption minimal due to LED usage. It can provide precise location information using lighting, and since communication does not work where there is no light, it can be safely used within specific spaces. Hacking is impossible unless you are under the same light bulb. Blocking the light alone can prevent hacking. It is also said to be safe for use on airplanes or deep underwater.

However, its strong directivity means there must be no obstacles blocking the light between Li-Fi transmitters and receivers, and it cannot be used when sunlight shines. Wi-Fi can transmit signals around corners even with obstacles. In other words, Li-Fi cannot be used if the light from the bulb does not reach, limiting signal transmission to restricted areas.

Despite these drawbacks, many companies see the advantages as greater and are rushing commercialization. Philips is testing Li-Fi technology with a French real estate company and currently offers integrated Li-Fi services including LED products and Li-Fi. Apple is reportedly considering adding source code for Li-Fi to the iPhone operating system iOS.

Nowadays, since most use energy-efficient LED lights, simply attaching a communication module to the light turns it into a Li-Fi device, which is an incomparable advantage. Rather than using Li-Fi as a replacement for Wi-Fi, if it is used to complement Wi-Fi’s weaknesses, wouldn’t wireless communication become more convenient and safer?