Engineer Harald Haas introduced Light Fidelity (Li-Fi) to the public in 2011 during a TED Global talk in Edinburgh. Li-Fi technology consists of a data transmission that utilizes visible light, ultraviolet, and infrared lights at high speed to carry out information for communication. It means that the data can be transmitted where these lights could reach. Only lamps, streetlights, or other light sources made from Light Emission Diodes (LEDs) can currently act as a medium for delivering/receiving network, information, and high-speed communication in a way similar to WiFi. LiFi is an Optical Wireless Communication (OWC) or Visible Light Communication (VLC) technology that works by switching the current to the LEDs on and off at a very high speed, about 10 billion times per second, which is not visible or unnoticeable by the human eye, reaching the speed up to 10Gbps.
It works by applying an electrical current to an LED light bulb, and it emits a stream of light (photons) that carries a data stream. We can modulate and increase the brightness of the light passing through them at extremely high speeds. By modulating the light at different rates, we can transmit a signal, which is binary. A detector receives the signal and interprets the changes in light intensity (the signal) as data. The modulation of light intensity, which we can not perceive through our eyes, gives us a seamless data transmission. The technology enables us to transmit data through LEDs at high speeds allowing the users have connectivity to LiFi where there are LiFi-enabled lights.
In wireless communication, the data transmission using LiFi is a new revolutionary paradigm that involves the trend toward a higher-frequency spectrum. LiFi can also work with daylight, including direct sunlight, in addition to LEDs. Indeed, Edinburgh, Scotland-based Pure LiFi, a pioneer in the technology, has designed and tested receivers outdoors under 77,000 lux of sunshine. We observed that its signal strength is unaffected by daylight's slower, gradual changes because it depends on detecting rapid changes in light intensity. Instead, a Li-Fi receiver filters out the sun's near-constant level of brightness, keeping the data stream intact.
A LiFi module (Wikimedia)
Looking back at its development
In the 1880s, Visible Light Communication ( VLC) is a concept that uses visible light in the electromagnetic spectrum to transmit data. Alexander Graham Bell and his assistant Charles Sumner Tainter pioneered and invented this device. The device was similar to the telephone at the time, which led to his famous invention of the Photophone. The only difference is that the Photophone used modulated light for wireless transmission rather than electrical signals carried over a wire circuit like the telephone. The Photophone transmitter received the sender's sound by picking it up at an aimed mirror. The resulting sound causes similar vibrations on the mirror and then projected back to the receiver as converted sound while they directed sunlight to the vibrating mirror. The invention gave birth to the idea of LiFi.
To put it simply, VLC is a concept that applies to all visible light-based communication systems. Li-Fi uses the same basic principles as VLC but provides high-speed network connectivity through a two-way network protocol. Prof. Harald Haas led a team of researchers at the University of Edinburgh who did much of the Li-Fi research. So, how does it work? Visible light is the primary carrier for data transmission medium in Li-Fi. We need a photodiode and a light source for this type of VLC system. The photodiode functions as a transceiver, receiving and transmitting light signals. The light source sends data over the medium of emitted light, which they used light-emitting diodes (LED) as a light source. The system employs a signal processing unit chip.
Hence LEDs are semiconductor materials; we can modulate the current provided to the bulb and the light they emit. This process happens at extremely high speeds that the human eye cannot perceive. We fed the data into the light bulb and then transmitted it to the photodiode at extremely high speeds. It transforms the data into a binary data stream that humans can understand, such as data streams in video and audio applications.
But how we transmit the data over light? The reason is Li-Fi systems need a solid, reliable light source, such as LED bulbs, to be able to perform data transmission over light. LEDs are unlike halogen or filament bulbs in that they do not require warming up. They are semiconductors, as previously mentioned. They soon start-up and emit light in response to the current that passes through them. We can embed data into the LED light by intensifying the colors red, green, and blue (RGB). We finely modulated it within the light spectrum. (Again, this is a procedure that goes unnoticed by the naked eye.) This fine RGB modulation is more accurate as a type of code for data transmission. We then demodulate the light after the photodiode received it. The received data is either transmitted to a cloud server or transcribed by the receiver. We translate and process the received code to display the content.
An illustration depicting a LiFi enabled workplace. (Wikimedia)
LiFi will not replace WiFi, but complement it.
Wireless data has become a necessary part of our everyday lives. WiFi is available anywhere, but we won't be able to use it permanently. The technology that drives WiFi, radiofrequency, is running out of bandwidth to keep up with the digital revolution. With each passing year, more people use wireless networking, bringing us closer to a problem known as the spectrum crunch. The term "spectrum crunch" refers to a possible scarcity of wireless frequency spectrum to accommodate an increasing number of consumer devices.
Spectrum scarcity is a threat to telecommunications and wireless networking that has far-reaching consequences shortly. WiFi will eventually be unable to keep up with the demand for data, and the world will need to future-proof our networks to meet the networking demands of the future. We may use a frequency that is 1000 times larger than the entire spectrum used by radio frequencies with Li-Fi. Thanks to its ability to generate small cells, Li-Fi allows considerably more access points than WiFi's radio frequencies, achieving the higher data rates needed for faster communication.
Haas shared that traditional WiFi will be incredibly inefficient due to several devices interacting in one location when we fully adapt to the Internet of Things (IoT). The ability to combine networking with mobile is a game-changing advancement in LiFi. The pace of data transmission and the ongoing miniaturization process solidifies the importance of adapting to LiFi. The applications of this technology are infinite and well beyond our imagination. Hence we encrypted the data in LiFi; hackers cannot intercept the data easily. We can use it in the military.
Besides, we can use LiFi in very remote locations and do not require any complicated wirings. Hence radio waves are absorbed by the water; we can't install WiFi underwater, but light can reach deep waters. It means that Li-Fi can be used for underwater communication, potentially altering how divers and underwater vehicles interact. It can allow us to understand underwater phenomena when we integrate remote sensors with LiFi. We must know that the invention of Li-Fi is not to replace Wifi but rather to enhance it. The capacity for LiFi to be adopted on a global scale is surprisingly easy. Homes across the world are readily equipped since billions of LED lights are already used unknowingly by them.
An illustration showing integration of LiFi in workspace. (Flickr)
It has a fair share of benefits and drawbacks.
In 2016, The announcement of WiFi HaLow became hype. It claimed to be able to double the WiFi range while using less power. Many people are anticipating its applications for increased mobile connectivity and the Internet of Things (IoT). By the way, WiFi HaLow is an extension of standard WiFi. On the other hand, liFi technology will outperform WiFi thanks to its impressive speeds.
While the full impact of 5G has yet to be felt, Li-Fi is already making waves as a potential booster for the next generation of wireless internet. LiFi reached speeds of up to 224 gigabits per second in lab tests, while 5G currently tops out at 10 gigabits per second. It gives LiFi technology its bestselling point, enables it to transmit data at a far greater speed than WiFi. When we have a faster connection, it means better service quality and dramatically clearer communication across the world. It gives Li-Fi the potential to facilitate the Internet of Things (IoT) and interconnectivity between devices.
Li-Fi's current operational principles focus on the use of LED bulbs and lamps as applications. As a result, we can integrate it easily into areas that already have LED lighting. The internet is available from everywhere where there is light, and it has a wide range of applications that require an internet connection. LED light bulbs are becoming a staple everywhere in homes, offices, businesses, and transportation due to people adopting green technology. As a result, high-speed internet connectivity will become as common as light bulbs in the not-too-distant future.
People are becoming more aware of the privacy and security concerns of having the internet. Eavesdropping, signal hijacking, and even brute force attacks have always been possible with RF (Radio Frequency) communication technology. In contrast, Visible light passes through opaque surfaces that are difficult to hack. We contained within one space the signals emitted by LiFi and the data transmitted. There is one issue with LiFi transmission, and it cannot passes through opaque objects why they will have a range limitation. However, we can mitigate it using sensors; hence it does not need a direct line of sight for visible light to travel. We can reduce their intensity to a level that they can continue to operate in a non-visible way.
The Li-Fi technology operates in a short-range. While this may be useful in the process of security, it also has drawbacks. Its operating range is limited by physical barriers. Lamps or bulbs must be strategically positioned in different rooms to broaden the reach. A single Wi-Fi router, on the other hand, has a greater range and is thus suitable for public networks. Light interference, such as sunlight, can disrupt Li-Fi signals. When other sources of light are present, it can be difficult for receivers to process signals.
Hence LED lamps must be turned on in order to function; they can contribute to light pollution, particularly if they are set to higher brightness levels to compensate for possible interference. We can also have problems with infrastructure. Although Li-Fi systems only use LED lamps, they should be relatively inexpensive to deploy. But due to a lack of infrastructure, the installation of Li-Fi systems can be costly. In addition, due to its limited range, multiple Li-Fi routers will be needed for increased connectivity. This will result in higher purchasing and installation costs. A small house, on the other hand, would only need one Wi-Fi router.
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