Light fidelity (Li-Fi) is an innovative technology that is steadily gaining traction in the telecom domain. While the concept of Li-Fi has been around for more than a decade, the technology has only recently gained momentum.

The global Li-Fi market is expected to grow rapidly in the coming years. Industry experts project a compound annual growth rate of 42 per cent for Li-Fi over the period 2022-30. This growth is being driven by several factors, including the increasing demand for high speed internet access, the growing adoption of smart devices, and the rising usage of internet of things.

Functioning of Li-Fi

In 2011, Harold Haas, a professor of mo­bile communications at the University of Edinburgh, coined the term “Li-Fi” in his TED talk on Visible Light Comm­uni­cation (VLC). During his talk, Haas de­mo­nstrated Li-Fi for the first time and in­troduced his concept of “wireless data from every light”.

Li-Fi is a wireless optical communication technology that utilises light to transmit data. Unlike Wi-Fi, which uses radio waves, Li-Fi employs the visible, ultraviolet and infrared light spectrum to transmit information. In simpler terms, Li-Fi is a light-based Wi-Fi that leverages the light spectrum, instead of radio waves, to transmit data.

Li-Fi uses standard light-emitting diode (LED) light bulbs to share information at high speeds that travel up to a hundred times faster than a conventional Wi-Fi network. This makes Li-Fi an ideal sol­ution for applications such as streaming hi­gh definition video, transferring large files, and connecting devices in dense ur­ban environments.

Li-Fi offers a promising alternative to traditional radio frequency technologies such as Wi-Fi. In addition to its superior speed, Li-Fi offers several other advantages over radio frequency technologies. Fi­rst, its optical spectrum resource is ab­out 3,000 times larger than the radio frequency spectrum resource, which enables Li-Fi to offer much higher speeds. Seco­nd, Li-Fi signals do not pass through wa­lls, providing greater data security. Third, Li-Fi does not interfere with radio frequency signals, making it ideal for use in environments where radio frequency emissions are restricted, such as hospitals and schools.

Components of Li-Fi

Visible light has a much higher bandwidth than radio waves, which means that it can transmit data much faster. This makes Li-Fi technology ideal for data-intensive applications, such as streaming high definition videos or downloading large files. Li-Fi is also full duplex, meaning that it can transmit and receive data simultaneously, and it can achieve data rates of up to 224 Gbps. For Li-Fi to perform seamlessly, several components are required.

Some of the major components re­quired include:

  • Data access points: The Li-Fi data acc­ess point is a device that connects Li-Fi-enabled devices to the internet. This is do­ne by using a high speed router and sw­it­ch to connect to the internet. The da­ta access point also uses advan­ced mo­dul­ation schemes and encryption techni­q­­ues to ensure that communication is secure.
  • Li-Fi-enabled light source: Li-Fi technology uses light to transmit data. Since LED bulbs, the light source used in Li-Fi, are semiconductors, the same light can be used for both lighting and data transmission by rapidly switching the LED light through advanced modulation techniques. Sophisticated transceivers act as both light sources for visible light and data transmission nodes capable of securely sending and receiving high speed data.
  • Li-Fi-enabled smart device (transceiver): A Li-Fi-enabled smart device is equipped with a photodetector, which acts as a receiver, and a light emitter, which acts as a transmitter, for both uplink and downlink communication. When the device moves out of the range of one light source and into the range of another light source, the system re-establishes connectivity in a manner similar to the traditional cellular concept.

Li-Fi versus Wi-Fi

The global Li-Fi market is growing rapidly due to the rising demand for wireless internet connectivity and the increasing need for secure, high speed data transmission technology with minimal interference. The increasing use of LED lights in Li-Fi systems is a major factor driving the growth of the global Li-Fi market. LED lights are inexpensive, readily available, consume less energy, and have a longer lifespan than traditional light sources, making them ideal for use in Li-Fi systems.

Li-Fi’s transmission speed significantly surpasses that of Wi-Fi transmissions. As previously mentioned, the highest achievable speed for Li-Fi is 224 Gbps. On a regular day, it is expected to move in the range of 10 to 20 Gbps. Li-Fi is estimated to be 100 times faster than WiGig, the current fastest Wi-Fi in the 60 GHz frequency band, which has attained maximum speed of 7 Gbps.

Another advantage of using Li-Fi over Wi-Fi is its utility. Li-Fi can be installed in places that are sensitive to electromagnetic waves, for example, airplanes or hospitals, without causing any interference or drop in network quality. While the electromagnetic spectrum used by Wi-Fi technology runs the risk of becoming saturated, it does not appear that the visible light spectrum (10,000 times greater) will face this issue in the short term.

Another advantage that Li-Fi brings to the table is its customisation capabilities. It is not necessary for the lights to be on at a le­vel perceivable to the human eye, and their intensity can be reduced so that they con­tinue to operate in a non-visible manner.

Li-Fi is also expected to be relatively inexpensive to implement. In theory, it would be sufficient to incorporate modulators into existing light fixtures and to include the necessary receivers in devices. Currently, developers are working to optimise the combined usage of Wi-Fi and Li-Fi for homes and offices.

A developing technology

Li-Fi is far from being a fully usable technology, as it has some significant drawbacks that offset its advantages over Wi-Fi. One major reason is that light, unlike radio waves, cannot pass through walls, which makes the connection more secure. But on the flip side, the limited range requires users to be close to the emitting lamp and ensure that their device is perfectly exposed to the emitted light to work properly. Further, for the widespread adoption of Li-Fi, there is a requirement for dedicated environments that can be wholly equipped with LEDs. Even though there are mobile terminals equipped with sensors compatible with the new technology, democratising this technology remai­ns a critical issue.

Innovations in India

As the new technology gains worldwide momentum and undergoes rigorous testing and trials to prove its viability, Li-Fi is marking its presence in India.

Sonam Wangchuk, a renowned Indian innovator, has come up with an avant-garde solution for providing internet connectivity in remote and challenging terrain by using Li-Fi. The world’s first mountaintop Li-Fi laser includes a laser transmitter perched at the mountain’s peak, converting radio signals into flickering lasers. It then receives optical signals from a telecom tower 3.5 km away, allowing the laser to transmit data to a receiver up to 10 km in distance, providing a bandwidth of 10 Gbps. The ingenuity of this technology becomes evident as it delivers high speed internet with stable internet connections of at least 400 Mbps, without the need for laying fibre connections.

Various universities and companies are also intensively working on fine-tuning the nuances of this technology. Earlier this year, Nav Wireless Technologies Private Limited signed an agreement with IIT Delhi to design indigenous Li-Fi networks based on visible lights. While Li-Fi is still in its nascent stage in India, further innovation and adoption of the technology are expected.

The final verdict

Li-Fi is not expected to replace Wi-Fi; on the contrary, it is anticipated to complement it and provide more benefits in terms of internet access. VLC technology is yet to be adopted by those who require higher data transfer speeds in a secure environment. This includes healthcare facilities, research laboratories, army camps, manufacturing plants and data centres. Further, this technology holds potential for companies focused on saving energy by reducing power consumption.

Recently, the Institute of Electrical and Electronics Engineers (IEEE) launched a new standard for Li-Fi – IEEE 802.11bb. This ground-breaking standard is desig­n­ed to provide a global framework for companies to deploy light-based devices that are compatible with each other, ushering in a new era of wireless communication. Due to these advancements, the global Li-Fi market is expected to reach $10.9 billion by 2030.