Can Li-Fi replace Wi-Fi?

Gen Z is the luckiest of all generations to witness the most extensive integration of technology into the smallest of human needs and activities. We have come a long way from dial-up internet connections to taking Alexa and Siri as companions in daily life. It is surprising that before the concepts of internet and artificial intelligence were discussed, seeds of WiFi (Wireless Fidelity) were sown by Hedy Lamarr, a Hollywood star cum passionate engineer in 1942. But here is some flash news - while WiFi is a household name now, we can’t use it forever.

WiFi utilizes radio frequencies for frequency hopping to transmit data. However, this spectrum is not unlimited. The Zettabyte era demands a larger spectrum to accommodate the expanding global IP traffic. It is not overwhelming that the number of devices connected to IP networks predicted by the Cisco _Annual Internet Report White Pape_r will be three times the global population by 2023. In this scenario, what if every light bulb in the world can be used to transmit data? Here is where LiFi (Light Fidelity) comes to the rescue. It is a visible light communication system that uses infrared and visible light spectrum for high-speed, bidirectional, and fully networked data communication. Prof. Herald Haas, a German Physicist, demonstrated this newfangled technology at TEDGlobal London in 2011.

Prof. Herald Hass at TEDGlobal London

WiFi technology has reached saturation in trying to accommodate internet traffic by spatial reuse of the radio frequency spectrum. By adapting LiFi, we are open to a range 2600 times larger than the former. Two main components of a LiFi system are the transmitter and receiver. The transmitter is a regular LED that will transmit data as binary codes by modulated illumination at a very high rate that is not noticeable to human eyes. The receiver is a photodiode that can decode the data transmitted based on illumination.

A LiFi network can be created when each light source in a room is driven by a LiFi modem or chip that serves as an optical base station. They are interconnected using high-speed backhaul connections. They will also have integrated infrared detectors to receive signals from the terminals. It is important to note that LiFi supports user mobility and multiuser access. Peak transmission speeds of 8 Gbps from a single light source have been demonstrated, and complete cellular networks based on LiFi have been created under research.

Reviews in Physics 3 (2018)

Currently, LiFi is still under testing and development. Given its potential, this technology can reach our homes in just a few years. The Global Market for LiFi Technology Analysis and Forecast 2018-2028 estimates that the global market will reach a value of near $36 billion in 2028_._ LiFi can scale up wireless communication anywhere globally, from aircraft to underwater ecosystems. Scientists have proven that a speed of 224 Gbit/s can be achieved with optimization. Since light does not penetrate walls, unlike radio waves, it ensures secure data transmission in a localized network. LiFi alleviates problems of interference with other systems and saturation of bandwidth. It also supports the vision of an environmentally sustainable future by consuming less power and providing accessibility even in remote locations. With LiFi, the Internet of Things can become a transcending phenomenon when proper lighting is all it takes to carry data. _“In the future, we will not only have 14 billion light bulbs, but we may also have 14 billion LiFis deployed worldwide for a cleaner, greener, and even brighter future,”_ Haas said.

However, LiFi faces hurdles to commercialization even though there are arguments that it is a fifth-generation technology. LiFi demands line of sight and hence has limited coverage. It might not be effective to deploy LiFi outdoors with sunlight. Therefore, LiFi can be expected to complement WiFi to overcome bandwidth limitations and not replace it in a more realistic scenario shortly. However, with research, a future run by LiFi can become a reality.

-Sneha Mary