With every technological advance, the world moves forward and we receive products that those from the past could only dream of. Li-Fi is one such emerging technology which might just take how we communicate to a completely new level. So far, we have been using radio waves for communicating and we are coming to a point when it can no longer be enough to fulfill the demands of our information consumption. To solve this problem, researchers have decided to use entirely different waves – light waves – that are ubiquitous and part of our everyday lives.
The term “Li-Fi” was coined by Professor Harald Haas of the University of Edinburgh and the co-founder of PureLiFi. He introduced the idea of Li-Fi during a 2011 global TED Talk, a technology that utilizes the same visible light energy we use for everyday lights.
Harald Haas is a professor of mobile communications at the University of Edinburgh, Scotland, who started researching Li-Fi in January 2010 and later formed his own company, PureLiFi. By October 2011, a few other companies and industry groups joined and formed the Li-Fi Consortium to exploit the possibilities and overcome the limitations of the radio wave-based wireless spectrum.
Li-Fi is a bi-directional, high-speed, and fully networked communication of data using light. It is a form of visible light communication (VLC) and a subset of optical wireless communications (OWC) which can be used to complement the normal Wi-Fi or completely replace it. It is also considered an excellent alternative to use in areas which are electromagnetic sensitive such as aircraft cabins, hospitals, or nuclear power plants, as it will not cause any interference.
Li-Fi’s spectrum is 10,000 times larger than that of radio frequencies and it has reached 224 gigabits per second during lab tests.
Until Li-Fi came into play, there were other VLC systems which could offer only uni-directional communication. As the research progressed, the speeds of Li-Fi increased. By August 2013, the researchers were able to increase the speed to 1.6 gigabits per second with a single color LED. In April 2014, a Russian company named Stins Coman was able to bring the speed up to 1.25 gigabytes per second with the hope of going to five gigabytes per second. Later the same year, Sisoft, a Mexican company, was able to increase the data transfer speed up to 10 gigabytes per second. The speeds have further gone up to 224 gigabits per second (28 gigabytes per second).
Li-Fi works by switching the LEDs on and off at a very high speed that the human eye cannot detect. The modulated light is then received by a photo-sensitive detector and demodulated to electronic form.
As LEDs are semiconductor devices, their brightness can be changed at an extremely high speed. For comparison, the lowest frequency at which lights are modulated is 1 MHz which is still 10,000 times higher than the refresh rate of our computer monitors. A Li-Fi dongle contains both the transmitter and the sensor to ensure bi-directional communication. Unlike Wi-Fi, it uses direct modulation methods similar to those used in remote controls.
Li-Fi has no problem working under sunlight of 77,000 lux. Though human eyes cannot perceive it, it can also be dimmed down at night. Unlike remote controls, Li-Fi doesn’t require direct line of sight to work. In fact, even the light reflected off the walls can achieve a data transmission rate of 70 megabits per second.
There are still a few obstacles for Li-Fi technology to overcome, but the possibilities are immense. For one, it is short-ranged as visible light cannot penetrate walls; but at the same time, this provides far more security than WiFi as it cannot be accessed and hacked from outside.
One of the possible interesting applications of Li-Fi is remotely operated, underwater vehicles (ROVs). Normally, ROVs rely on cables to receive commands and send signals. This limits the vehicle’s ability to reach distances farther than the length of the cable. Using Li-Fi in hospitals also provides a better system to transmit information, and also the light waves have little effect on medical equipment or human bodies. Home and building automation is considered another possible area of application. As the waves cannot penetrate walls, the buildings cannot be hacked from a remote location.
Many companies such as PureLiFi, OLEDComm, Qualcomm, Panasonic, Samsung, and Philips are working on developing the technology to make it easily available to everyone.