Li-Fi is a technology that uses visible light to transmit data, offering speeds up to 10,000 times faster than traditional wireless communications due to its wider frequency band. It has advantages such as energy efficiency, security, and solving data throughput problems, and is being touted as the next big thing in communications.

Data transmission using visible light

Li-Fi is being touted as the next big thing in communications, and it takes an innovative approach to transmitting data that’s different from traditional communication methods – specifically, it uses visible light. Visible light is light that we can see, but the idea that it can be used as a means of communication is probably a new concept to many people. This innovation is possible thanks to advances in science and technology, and the high bandwidth of visible light’s frequencies has opened up the technical possibility of transmitting more data at once.
In recent years, we’ve witnessed the evolution of Long Term Evolution (LTE) technology to Long Term Evolution Advanced (LTE-A). LTE-A offers speeds that are three times faster than existing LTE, which represents a major advancement in communication speed. Korea’s three major telecoms companies (SK Telecom, KT, and LG U+) all offer broadband LTE-A services. However, as telecoms technology advances, users’ data usage is also increasing rapidly. In particular, new services are requiring more and more data, which is exacerbating the traffic problem. So what can be done to handle the explosion of traffic? Li-Fi could be the answer.
The technology was proposed by Professor Herald Haas of the University of Edinburgh in the UK, who devised a way to use the light from LED bulbs to transmit data, and the principle is quite simple. An LED bulb can blink more than 200 times per second, and this blink rate is used to transmit the 1s and 0s of data – for example, when the bulb is on, it represents a 1, and when it is off, it represents a 0. This principle is very efficient and opens up the possibility of transmitting data faster than traditional communication methods.

Why visible light?

So why use visible light out of all the electromagnetic waves? Visible light has a number of properties that make it ideal for lifelines. First, visible light can be detected by the human eye, but its fast flicker rate is not perceived by the human eye, meaning it can do double duty as the light we use every day and transmit data at the same time.
Second, the frequency of visible light is very high, allowing it to transmit much more data simultaneously than radio waves. The frequency band of visible light is more than ten thousand times wider than that of radio waves, and this wider bandwidth can be utilised to transmit large amounts of data at once. In this respect, it is a much more efficient use of frequency resources than radio waves.
Third, visible light has the property of being highly linear. This means that it has less diffraction (the ability to pass through obstacles) than radio waves. In other words, while it can sometimes be difficult to send data through walls, this characteristic can actually be a huge advantage in terms of security: it’s impossible to communicate where light can’t reach, reducing the risk of hacking.

Advantages of lifelines

The first advantage of Lifai is that it can utilise existing infrastructure: the LED light bulbs we already use as communication devices can be used to communicate without the need for any additional equipment. Also, traditional communication equipment uses a lot of energy to keep cool, but Lifai can reduce this energy waste, making it an environmentally friendly technology.
The second advantage is the increase in data transmission speed. Thanks to the wide bandwidth of visible light, more data can be transmitted simultaneously, which is achieved through OFDM (orthogonal frequency division multiplexing) technology. Because this technology can transmit data by dividing it across multiple frequencies, it can significantly increase traffic throughput. Especially with the recent surge in data usage, lifelines can be an important alternative to solve traffic problems.
It’s also highly secure thanks to the straightness of visible light. If the light is blocked, communication is impossible, reducing the risk of hacking, which is the illegal interception of communications from the outside. This is a big difference in security when compared to traditional Wi-Fi, which uses radio waves.

Disadvantages and solutions

Of course, there are downsides to lifelines. One of the biggest is the difficulty of building the infrastructure. You’ll need to replace existing incandescent bulbs or LED bulbs that don’t support lifelight with lifelight-ready LED bulbs, which can be expensive upfront, but will pay for itself in the long run thanks to energy savings and speed improvements.
The straightness of the visible light also poses the problem that if the light is blocked or there are obstacles, communication can be lost. However, these issues can be overcome by using it in parallel with traditional Wi-Fi. For example, using Li-Fi as the primary means of communication, but allowing Wi-Fi to play a secondary role in areas where light is blocked, can help maintain continuity of communication.

Conclusion: Potential as a future communication technology

Lifai has the potential to deliver speeds that are theoretically 10,000 times faster than conventional communications. It is also an eco-friendly and secure way to communicate, and could play an important role in the future communications infrastructure. Coupled with infrastructure improvements, such as government-led LED lighting programmes, it could soon become a ubiquitous part of our daily lives.
Finally, Professor Haas imagines a bright future for this technology. ‘In the future, not only will we have 140 trillion light bulbs, but we will also have 140 trillion Li-Fis installed around the world for a cleaner, more environmentally friendly, and hopefully brighter future.’