LI-FI: A NEW TOMORROW OF DATA TRANSFER

With the advancement of technology, people are now totally depended on virtual data. This virtual dependency is increasing the amount of data storage day by day. With the increase in the amount of data day by day, people are demanding faster data transfer technology at low cost. Well, the advancement in data transfer technology we have achieved a pretty high-speed technology which is available as 4G and in few countries like US 5G is also an option. These connections provide a maximum of 150-200 Mbps of average speed. Wi-fi is a very good option in terms of data transfer. It provides a maximum of 200Mbps (WLAN-11n) and 1-2 Gbps (WiGig/Giga-IR).

The urge of high-speed data transfer has triggered the invention of a new technology called Li-fi. What is Li-fi? It is the short form of “Light Fidelity”, very similar to a Wi-fi, it is an optical wireless network communication system. Li-fi network can be powered by Light Rays from either the visual range or the Infrared (IR) or Ultraviolet Region. A striking advantage of Li-fi over Wi-fi is that it can boost the network speeds about 100 times faster than the conventional Wi-fi system available. Although Li-fi can be used by using any of the above-mentioned light spectra, according to the present technology, it can only be used by using VLC (Visible Light Communication) technology. Why Li-fi is faster than other technology? As Li-fi uses light to transfer data, which is much faster than RF (Radio Frequency) used by Wi-fi and MM Waves used by 4G and 5G, that is why it is 100 times faster than other technologies.

History

Harald Haas

The term Li-fi has been coined by Professor Harald Haas, the  co-founder of PureLifi and a professor of Mobile Communications at the University of Edinburgh, at his 2011 TED Global Talk where he introduced the idea of “wireless data from every light”. Although the history of Li-fi is very short, the technologies used for the proper functioning of Li-fi is take us back in the year 1880. On February 19, 1880, Alexander Graham Bell and his assistant Charles Sumner Tainter jointly invented the photophone. The photophone was a device that wirelessly transmitted speech using a beam of light. Bell considered the photophone as one of his most important inventions. It was revolutionary as it was the first to utilize modulated light for communication. It also served as a precursor to various optical communications technologies including fiber optics and VLC. With the limitations of the present technology, Li-fi can only be used by using VLC.

Who does Li-fi Work?

Li-fi is a derivative of optical wireless communications (OWC) technology, which uses LEDs as a medium to deliver data at very high speed in a similar manner to Wi-fi. As mentioned before Li-fi uses VLC for data transmission.  A VLC system has two qualifying components:

1.     At least one device containing a photodiode to receive light signals.

2.     A light source equipped with a signal processing unit for the transmission of signals.

This is an important quality to look for in a VLC light source because Li-fi relies on the constant stream of photons emitted as visible light for the transfer of data. When the current applied to the light source is varied slowly, the light source dims up and down, which makes it unsuitable as a source of light, not for the Li-fi system, but as a device for household illumination. To strike a balance between VLC light source and household illumination, this current as well as the optical output is modulated at extremely high speeds, making it detectable by the photodiode device and converted back into electrical current, but unperceivable by the human eye. Once these signals are received and demodulated, they can now be converted into a continuous stream of binary data that contain videos, images, audio, text, or applications that are readily-consumable on any internet-enabled device.

Li-fi Consortium and Other Developments

In 2011, four industry leaders from four different countries created a group that seeks to enhance and promote different Optical Wireless Communication (OWC) technologies. The group was known as the Li-fi Consortium. It was founded by Fraunhofer IPMS, Germany, IBSEN telecom, Norway, Supreme Architecture, Israel/USA, and TriLumina, USA. The focus of the consortium is not limited to Li-fi, however, as previously stated. Instead, it pushes for the advancement of all forms of OWC, which include Li-fi and fiber optics, among others.

Advances in Li-fi technology were on display over the years. In August 2013, Li-fi systems were able to demonstrate data rates of over 1.6 Gbps over a single colour LED. In October 2013, Chinese manufacturers were working on Li-fi development kits. The scientists say data speed of up to 150 Mbps were possible using microchipped bulbs. In April 2014, Russian company Stins Coman announced their development of Beam Caster, a Li-fi wireless local network capable of transferring 1.25 gigabits of data per second. They foresee boosting speeds of up to 5 Gb/s soon.

Applications

There are many applications of Li-fi in the present day. As it uses the light source people may use it for various purpose. Here are the top 5 applications of Li-fi technology.

1.     Cellular Communications: Li-fi can take pride in the fact that it can provide high-speed data communication 24/7 by turning normal streetlights into network access points. Communication costs would therefore be significantly reduced because there would be no need to install radio bases. In other words, streetlamps would provide both, data communication and lighting.

2.     High Capability: In a room, any user of Li-fi can get a high-speed data connection no matter how many users are connected. This is possible given the fact that the area of the channels is determined by the light range provided by the LED lamp. Each light pool provides full channel data rates with fewer simultaneous users than conventional radio technology.

3.   Security: The the greatest asset of Light communications is that light can’t go through walls, hence data security is enhanced concerning radio-based networks.

4. Underwater Communications: Unlike radio waves, which are easily absorbed by water, light waves can travel great distances. This remarkable property allows diver-to-diver or diver-to-minisub communications, even if they are miles apart.

5.     Intelligent transportation System: Li-fi could potentially prevent car collisions through proximity warnings, which can be transmitted from car to car using their tail or headlights. This also would allow real-time to download useful information, such as the optimal routes to take.

Advantages of Li-fi

·       Efficiency: Li-fi works on visible light technology. Since homes and offices already have LED bulbs for lighting purposes, the same source of light can be used to transmit data. Hence, it is very efficient in terms of costs as well as energy. The light must be on to transmit data, so when there is no need for light, it can be reduced to a point where it appears off to human eye but is still on and working.

• Availability: Wherever there is a light source, there can be the Internet. Light bulbs are present everywhere – in homes, offices, shops, malls and even planes, meaning that high-speed data transmission could be available everywhere.
• Security: One main advantage of Li-fi is security. Since light cannot pass through opaque structures, Li-fi Internet is available only to the users within a room and cannot be breached by users in other rooms or buildings.

Disadvantages of Li-fi

• Internet cannot be used without a light source. This could limit the locations and situations in which Li-fi could be used.
• Because it uses visible light, and light cannot penetrate walls, the signal's range is limited by physical barriers.
• Other sources of light may interfere with the signal. One of the biggest potential drawbacks is the interception of signals outdoors. Sunlight will interfere with the signals, resulting in interrupted Internet.
• A whole new infrastructure for Li-fi would need to be constructed.

Li-fi VS Wi-fi

Features	Li-fi	Wi-fi
Full form	Light Fidelity	Wireless Fidelity
Operation	Li-fi transmits data using light	Wi-Fi transmits data using radio waves
Interference	Do not have to aby interference issues like radiofrequency waves.	Will have interference issues from nearby access points(routers)
Technology	Present IrDA compliant devices	WLAN 802.11a/b/g/n/ac/ad standard-compliant devices
Applications	Used in airlines, undersea explorations, operation theatres in the hospitals, office and home premises for data transfer and internet browsing	Used for internet browsing with the help of Wi-Fi kiosks or Wi-Fi hotspots
Merits	Interference is less, can pass through salty seawater, works in a dense region	Interference is more, cannot pass through seawater, works in a less dense region
Privacy	In Li-fi, light does not pass through the walls and hence will provide a much secure data transfer	In Wi-fi, RF the signal passes through the walls and hence there is a need to employ techniques to achieve secure data transfer.
Data Transfer Speed	About 1 Gbps and up to 5 Gbps in future	WLAN-11n offers 150Mbps, about 1-2 Gbps can be achieved using WiGig/Giga-IR
Data Density	Works in high dense environment	Works in less the dense environment due to interference related issues
Coverage Distance	About 10 meters	About 32 meters (WLAN 802.11b/11g), vary based on transmit power and antenna type
System Components	Lamp driver, LED bulb(lamp) and photodetector will make up a complete Li-fi system.	Requires routers to be installed, subscriber devices (laptops, PDAs, desktops) are referred to as stations
Frequency of Operation	10 thousand the time's frequency spectrum of the radio	2.4GHz, 4.9GHz and 5GHz

Table courtesy: https://www.rfwireless-world.com/Terminology/Li-fi-vs-Wi-fi.html

The introduction of Li-fi is certainly a welcome one. Of course, with limitations in basic infrastructure, the total replacement of Wi-fi in favour of Li-fi is next to impossible. However, what it does present is a viable option that can be used as an alternative especially in areas that are sensitive to the prevailing technology. It has, however, succumbed to many different factors that have also affected its performance. These factors include congestion, limitations of use due to interference with other functions, and bandwidth saturation, which clearly exposes the shortcomings of this existing technology.

Lastly, do comment and share your views for the betterment of the content. Write do the topics on which you would like to see my blogs. Do mention if I missed anything that should be in the blog. Share it if you like it and follow my blog to get yourself introduced to the future of humankind. Log-in to my page https://techgenix99.blogspot.com/ to keep yourself up-to-date in the field of technology.

References:

·        https://lifi.co/

·        https://hitricks.com/li-fi-internet-advantages-disadvantages-lifi-vs-wifi

·        https://www.techopedia.com/7/31772/technology-trends/what-are-the-advantages-and-disadvantages-of-li-fi-technology#:~:text=Advantages%20of%20Li-Fi%20technology%20include%3A%201%20Efficiency%3A%20Li-Fi,within%20a%20room%20and%20cannot%20be%20breached%20

·        https://lifi-information.com/lifi-applications/