By Peter Vowell
Light Fidelity (Li-Fi) is a visible light communication technology, capable of transmitting information via light. It uses light emitting diodes (LEDs) in combination with signal processing technology to transmit data via modulations in light levels.
As semiconductor devices, LEDs can be turned on and off very rapidly. Li-Fi technology transmits data by adjusting the LED light intensity in ways that can be picked up by photo-detecting receivers. The receiver converts the light signal back into an electrical one (data), which can then be interpreted by all of our modern processing technologies.
The most notable achievement of Li-Fi is its ability to reach speeds of up to 224 gigabits per second. This is around 100x faster than the current average Wi-Fi speed. It should be noted that these speeds are only achievable when the receiver is directly exposed to the light emitted from the LED. The signal will decay significantly if the photo detector is only receiving a reflected beam.
One might therefore think that Li-Fi signal strength is directly correlated to the distance from the source (LED light intensity), but the data actually dwells in the difference between light levels. A signal can therefore be sent even when light intensity is very low. Signal distortions (i.e. light pollution) in low light settings, however, do impact the data transfer rate. This is explored further in the next section.
Li-Fi holds a distinct advantage with regards to security. Both Wi-Fi and Li-Fi use electromagnetic waves for the transmission of information, but Li-Fi uses photons as opposed to radio waves. Radio waves will pass through most objects: people, walls, furniture, etc. Light does not share this trait, which means that the transmitted signal can only be intercepted if someone is in the direct path of the light being emitted. This translates to easier monitoring of who is using your network, thus increasing network security.
This new technology is also more energy efficient than traditional Wi-Fi transmitters, since the only active component of the Li-Fi system is the LED current being modulated. LEDs are extremely low power devices, using only a fraction of the energy consumed by incandescent and fluorescent light bulbs. Even with the added power draw of the signal-processing unit, the power draw of Li-Fi is significantly lower than that of a Wi-Fi transmitter.
One of Li-Fi technologies biggest assets is also one of its biggest flaws. The fact that the photons cannot be transmitted through objects allows for added information security. However, it also means that the LED light bulbs would have to be placed at a much higher density throughout a home or office space than is considered traditional in order to achieve a continuous network throughout a given space. In addition, all of these lights would have to be on in order to have a network connection.
Another major drawback is the inability of Li-Fi to tolerate the presence of other light sources. The light from the sun, for example, would distort the Li-Fi signal. As a result, the receiver would no longer distinguish the minor fluctuations from the transmitting source. For the end user, this means Li-Fi cannot be implemented outdoors, or even in a naturally lit space.
Li-Fi presents a unique opportunity for the business sector. LEDs consume a fraction of the power that fluorescent lights consume, providing significant economic savings. In addition, eliminating the power-hungry transmitters and range boosters involved with Wi-Fi would lead to an even more financially efficient office setup. The added security that is inherent to Li-Fi would decrease the strain and stress on IT and networking departments, freeing them up to tackle larger issues.
The main challenge involved with a Li-Fi office setup comes from external light pollution. If the receiver is place beneath any non-Li-Fi enabled lighting source, the signal will distort. The receivers would also need to be placed in a setting removed from natural light. These work settings are rare because natural light is often associated with employee health and happiness. While Li-Fi provides some noteworthy advantages, it isn’t quite ready to be implemented as a practical solution in most spaces.
Another challenge that Li-Fi faces is acceptance by major technological companies and communities. Transmitting data efficiently is only half the challenge: users have to be able to receive the data as well. Even if it fully develops into an easily implementable technology, it won’t matter unless people and companies choose to buy into the idea. Apple is currently rumored to be researching the idea of implementing Li-Fi capability into the next wave of iPhones, but as of yet this is unconfirmed. They are currently the only company that has expressed any public interest. Li-Fi is not expected to become a viable, fully developed technology until mid-2018.
There are three main companies who are publicly declaring their dedication to Li-Fi. Leading the pack is pureLiFi. Formed by Harold Haas, a professor widely regarded as the primary inventor and “father” of Li-Fi technology, pureLiFi currently has two products available for consumer consumption. Despite having a fully-fledged product ready for sale, the range remains poor and the speed doesn’t approach anything close to Li-Fi’s maximum potential.
The second manufacturer is a French company by the name of OLEDCOMM. Of the six development kits available, none are economically viable yet. The third company, Visilink, is based out of Japan. They have products similar to that of pureLiFi, but none of which are ready for large-scale implementation.
Li-Fi is a relatively simple technology that has the potential to reach speeds up to 100x faster than Wi-Fi. It offers greater security, reduced power consumption, and statistically significant economic savings for businesses. However, Li-Fi still needs time to grow as a product, and is currently too immature a technology to be implemented on a large scale. Though it may be another two years before it emerges as a viable alternative, Li-Fi will bring data transmission to a whole new wavelength.
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