Li-Fi: A green avatar of Wi-Fi

Li-Fi is not expected to completely replace Wi-Fi, but the two technologies could be used complementarily to create more efficient, green and future-proof access networks

Li-Fi is not expected to completely replace Wi-Fi, but the two technologies could be used complementarily to create more efficient, green and future-proof access networks.

Li-Fi, or light fidelity, invented by German physicist and professor Harald Haas, is a wireless technology that makes use of visible light in place of radio waves to transmit data at terabits per second speeds—more than 100 times the speed of Wi-Fi.

Though it was discovered in the last decade, proofs of concept to test commercial utilization started emerging only in 2015. To start with, it is being tested for indoor usage, i.e., in offices and establishments, but it is also sure to go outdoor in a big way by making use of existing infrastructure used for street and traffic lights, which are already moving towards LED lamps.

Li-Fi offers great promise to overcome the existing limitations of Wi-Fi by providing for data-heavy communication in short ranges. Since it does not pollute, it can be called a green technology for device-to-device communication in the Internet of Things (IoT).

Move towards greener wireless communication

A technical solution for wireless pollution, power shortages and unavailability at outdoor locations should meet the 3L criteria: low interference, low power and low maintenance.

In addition, it has to support the three Hs of high data rates, high reliability and high affordability. Since Li-Fi relies on visual light and not radio waves as the carrier, it has potential for the first two Hs, but the last one—high affordability—may be achieved only when volumes increase, as it has in the case of Wi-Fi.

The above characteristics can be met by an all-IP (packetized) Li-Fi system utilizing existing LED lamps which are ruggedized, have a high MTBF (mean time between failure) and consume less power, therefore replacing conventional lamps on existing structures in both indoor as well as outdoor without need for any additional power supply.

To make LED lamps capable of working as an access point as in Wi-Fi, a kind of media converter is required to convert the electrical data signal into photons (light), and a light detector which converts light into electricity is required on the receiving device end.

Potential applications

Li-Fi is still in its infancy, but some fields where it seems eminently usable are street and traffic lights. Traffic lights can communicate to the vehicles and with each other. Vehicles having LED-based headlights and tail lamps can communicate with each other and prevent accidents by exchanging information. Also, through the use of Li-Fi, traffic control can be made intelligent and real-time adaptable. Actually, each traffic and street light post can be converted into access points to convert roadsides into wireless hot spots.

Visible light being safer, they can also be used in places where radio waves can’t be used such as petrochemical and nuclear plants and hospitals. Similarly, in aircraft, where most of the control communication is performed through radio waves, there are restrictions on passenger communication using the same media, which can be easily handled through use of Li-Fi.

Li-Fi can also easily work underwater, where Wi-Fi fails completely, thereby throwing open endless opportunities for military and navigational operations. Still, the technology comes with some limitations.

As visual light can’t pass through opaque objects and needs line of sight for communication, its range will remain very restricted to start with. Also, it is likely to face interference from external light sources, such as sunlight and bulbs, and obstructions in the path of transmission, and hence may cause interruptions in communication.

Also, initially, there will be high installation costs of visual light communication systems as an add-on to lighting systems. Li-Fi receiving devices will require adapters to transmit data back to the transmitter.

Challenges and opportunity in India

The lack of ubiquitous broadband access, which thereby restricts data access, and chaotic traffic management leading to traffic jams and pollution are just two of the many problems in India. Li-Fi has scope to help with both. By converting traffic lights into LED-based access points, traffic management can be made intelligent, adaptive and real-time—and so, more efficient and effective. In the same way, street lights can also be converted into Li-Fi access points, making them broadband access transmitters to mobile Li-Fi enabled smartphones, converting areas into seamless hot spots.

The main challenge is to create a Li-Fi ecosystem, which will need the conversion of existing smartphones into Li-Fi enabled ones by the use of a converter/adapter. Also, an integrated chip that has both light-to-electrical conversion and data-processing capability (Wi-Fi/Bluetooth) combined into one needs to be developed and manufactured in the millions. This is one opportunity where the country can capture the initial lead advantage, making up for earlier missed cases.

If Li-Fi can be put into practical use, every LED lamp (indoor as well as outdoor) can be converted into something like a hot spot to transmit data to every mobile device to achieve universal broadband communication between devices. Also, it presents another unique possibility: transmitting power wirelessly, wherein the smartphone will not only receive data through Li-Fi, but will also receive power to charge itself.