LiFi

LiFi (Light Fidelity) and its applications
FN Division, TEC
Submitted by Sanjana.k
4th semester, Department of Information Science
Brindavan College of Engineering, Bangalore.
Abstract: – Li Fi stands for light fidelity . The understanding is very fresh and become projected with the aid of the German physicist Harald Haas in 2011 TED (technology , leisure , design ) international speak on visible light communication (VLC). LiFi is a wireless optical networking era that makes use of light emitting diodes (LEDs) for communication of records
The word LiFi refers to visible light communication (VLC) technology that uses light as intermediate to supply excessive speed conversation in a way comparable to Wi Fi and comply with the IEEE favored IEEE 802.15 .7.

Li-Fi technology is based on LEDs for the transfer of information. The transfer data may be with the assist of all sorts of light, irrespective of the part of the spectrum that they belong. That is, the light can belong to the invisible, ultraviolet or the seen component of the spectrum. Also, the velocity of the net is exceedingly excessive and you could down load films, games, sound etc in only a few mins with the help of this generation .

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Li Fi offers better bandwidth , efficiency , connectivity and protection than Wi -Fi and has already done excessive speeds large than 1 Gbps beneath the laboratory situations. The advantage is the low-cost nature of LEDs and lighting devices , there are plenty of opportunities to exploit this medium . Li Fi is the switch of data via light by way of taking fibre out of fibre optics and sending information thru gh LED light bulb (proven in Fig 1).

KEYWORDS: LED (Light Emitting Diode), WiFi (Wireless Fidelity), LiFi (Light Fidelity), VLC (Visible Communication), RF (Radio Frequency).Light
Introduction
In easy phrases, LiFi can be thought as a light based wi-fi. That is, it uses light instead of radio waves to transmit facts. And alternatively of Wi Fi modems, Li -Fi would use transceiver – equipped LED lamps that can light a room as properly as transmit and get hold of records. Given that simple light bulbs are used, there can technically be any wide variety of get right of entry to points. This technology uses a part of the electromagnetic spectrum that is nevertheless not greatly utilized The seen Spectrum. light is in truth very a great deal component of our lives for tens of millions and thousands and thousands of years and does not have any most important sick impact. Furthermore there is 10,000 instances greater area to be had in this spectrum and simply counting on the bulbs in use, it additionally multiplies to 10,000 times extra availability as an infrastructure, globally .

How Li-Fi Works?
Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made t o vary at extremely high speeds.

This very property of optical current is used in Li -Fi setup. The operational procedure is very simple-, if the LED is on, you transmit a digital 1, if it’s off you transmit a 0. The LEDs can be switched on and off very quickly , which gives nice opportunities for transmitting data. Hence all that is required is some LEDs and a controller that code data into those LEDs. All one has to do is to vary the rate at which the LED’s flicker depending upon the data we want to encode .

Further improvements can be made in this method, like the usage of an array of LEDs for parallel facts transmission, or the usage of combos of pink, inexperienced and blue LEDs to alter the lights frequency with every frequency encoding a distinct records channel. Such improvements promise a theoretical velocity of 10 Gbps – that means you’ll be able to down load a complete high-definition film in just 30 seconds.

To in addition get a draw close of Li-Fi recollect an IR far away. It sends a unmarried information move of bits at the charge of 10,000-20,000 bps. Now update the IR LED with a light field containing a large LED array . This gadget, is capable of sending heaps of such streams at very speedy charge.

Light is inherently secure and can be used in places wherein radio frequency conversation is regularly deemed elaborate, as in plane cabins or hospitals. So seen light communication no longer most effective has the potential to solve the problem of lack of spectrum space, but can also allow novel utility. The visible light spectrum is unused, it’s no longer regulated, and can be used for verbal exchange at very high speeds.

Comparison Between Li-Fi and, Wi-Fi and other Radio Communication technologies.

Table 1: Comparison of speed of various wireless technologies
Technology Speed
LiFi ~1Gbps
Wifi-IEEE ~150Mbps
IrDA ~4Mbps
Bluetooth ~3Mbps
NFC ~424Kbps
Parameter Lifi Wifi
Spectrum Visible light Radio frequency
Standard IEEE 802.15.7 IEEE 802.11
Range <10m <300m
Data Transfer Very high low
Power consumption Low High
cost Low High
Bandwidth Unlimited limited
How it is different ?
Li-Fi technology is based on LEDs for the transfer of data. The transfer data can be with the help of all kinds of light, no matter the part of the spectrum that they belong. That is, the light can belong to the invisible, ultraviolet or the visible part of the spectrum. Also, the speed of the internet is incredibly high and you can download movies, games, music etc in just a few minutes with the help of this technology .

Also, the technology removes limitations that have been put on the user by the WiFi. You no more need to be in a region that is Wi-Fi enabled to have access to the internet. You can simply stand under any form of light and surf the internet as the connection is made in case of any light presence. There cannot be anything better than this technology ?

Why Visible Light Communication:
The frequency spectrum that is available to us in the atmosphere consists of many wave regions like X-rays, gamma rays, u-v region , infrared region , visible light rays, radio waves, etc. Any one of the above waves can be used in the upcoming communication technologies but why the Visible Light part is chosen? The reason behind this is the easy availability and lesser harmful effects that occur due to these rays of light . VLC uses the visible light between 400 THz (780 nm ) and 800 THz (375 nm ) as medium which are less dangerous for high -power applications and also humans can easily perceive it and protect themselves from the harmful effects whereas the other wave regions have following disadvantages: –
Radio waves are expensive (due to spectrum charges) and less secure (due to interference and possible interception etc.)
Gamma rays are harmful because it could be dangerous dealing with it , by the human beings due to their prove adverse effects on human health .
X-rays have health issues, similar to the Gamma Rays.

Ultraviolet light can be considered for communication technology purposes at place without people, otherwise they can also be dangerous for the human body when exposed continuously .
Infrared, due to high safety regulation , can only be used with low power.

Hence the Visible light portion ( from red to blue) of the electromagnetic spectrum does not cause any harm to the people as visible rays are safe to use , provide larger bandwidth and also have a promising future in the communication field.

Li-Fi can solve problems related to the insufficiency of radio frequency bandwidth because this technology uses Visible light spectrum that has still not been greatly utilized.

High data transmission rates of up to 10Gbps can be achieved.

Since light cannot penetrate walls, it provides privacy and security that Wi -Fi cannot.

Li-Fi has low implementation and maintenance costs.

It is safe for humans since light, unlike radio frequencies , cannot penetrate human body .

Hence, concerns of cell mutation are mitigated.

Disadvantage of LI-FI
• light can not bypass through objects.

•A main mission dealing with Li-Fi is how the receiving tool will transmit returned to transmitter.

•High set up price of the VLC structures .•Interferences from outside light resources like solar, mild, ordinary bulbs, opaque substances.

Issues with Wifi which can overcome by Lifi
The following are the basic issues with radio waves:
a) Capacity : wi-fi records is transmitted thru radio waves which are constrained and high priced. It has a restricted bandwidth. Li -Fi : With the rapidly developing international and improvement of technologies like 3G, 4G and so on we are jogging out of radio spectrum .

b ) Energy Efficiency : There are a big quantity of cell radio base stations that consume big amount of electricity . Most of the power is used for cooling down the base station instead of transmission . Therefore, performance o f such Radio base stations is very low.

c) Availability : Availability of radio waves is a big difficulty . In addition, Radio waves are not really useful to be used in aero planes and at places where radio interference may also cause undesirable end result .

d) Security : Radio waves can penetrate via partitions . They can be intercepted. If someone has know-how and awful intentions, they might also misuse it . This reasons a primary security subject for Wi – Fi .

Applications
1.Traffic lights :
•Traffic lighting can speak to the cars and with every other.Vehicles have LED-based totally
based headlights,LED primarily based cack lighting and automobiles can talk with every other and prevent injuries in which the aid of replacing records. In cars and traffic lighting ,lowering injuries and traffic congestion

2.Airlines :
•Each time we travel through airways we face the issues in communication media, due to the fact the whole airways conversation are carried out on the basis of radio waves .To triumph over this draw back on radio waves ,lifi is brought .

3.Intrinsically Safe Environment :
•visible lighting fixtures is more safe than RF, therefore it may be used in places wherein RF
Cant be used inclusive of petro chemical plants.

4.Hospitals :
Can be used within the places where it is difficult to lay the optical fiber like hospitals. In operation
•theatre LiFi may be used for cutting-edge medical units

5.On Ocean Beds:
Lifi can never work underneath water were WifiFails absolutely , thereby throwing open limitless possibilities for navy or navigation operations.

CONCLUSION
The possibilities are numerous and can be explored further. If this technology can be put into practical use, every bulb can be used something like a Wi-Fi hotspot to transmit wireless data and we will proceed toward the cleaner, greener, safer and brighter future. The concept of Li-Fi is currently attracting a great deal of interest, not least because it may offer a genuine and very efficient alternative to radio-based wireless. As a growing number of people and their many devices access wireless internet, the airwaves are becoming increasingly clogged, making it more and more difficult to get a reliable, high-speed signal. This may solve issues such as the shortage of radio-frequency bandwidth and also allow internet where traditional radio based wireless isn’t allowed such as aircraft or hospitals. One of the shortcomings however is that it only work in direct line of sight