International Journal of Research & Development in Technology

International Journal of Research & Development in Technology and Management Science –Kailash

Volume - 21| Issue 6 | MARCH 2015 | ISBN - 1-63102-450-7 European Article Number [EAN] - 978-163-102-450-4

[email protected] | [email protected] | http://journal.rtmonline.in | http://www.ijrdtm.com

Paper Id: IJRDTM –053076

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LI-FI TECHNOLOGY: THE FUTURE OF WIRELESS

COMMUNICATION

by

Pankaj Sareen | Assistant Professor | SGGS Khalsa College | Mahilpur |

[email protected]

&

Dr. Tripat Deep Singh | Assistant Professor | GNIMT | Ludhiana | [email protected]

ABSTRACT

In today’s wireless technology era, usage of internet is growing at a great

pace. Presently radio waves are used for wireless communication. But this

technology will soon become obsolete due to consequences like limited

bandwidth and speed, security, efficiency, and an increased risk of radio

waves interference. To overcome such problems, the emerging concept of

transmitting data wirelessly through light using LED’s came in to

existence which is fast, reliable and error free. The term Li-Fi, or light

fidelity is increasingly being used to refer to the use of Visible Light

Communication (VLC) technology in wireless computer networking. In

this system, LED’s devices are used not only for illuminating rooms, but

also for an optical wireless communication system. Li-Fi Technology can

produce data rates faster than 10 megabits per second, which is

speedier than your average broadband connection. The Li-Fi market is

projected to have a compound annual growth rate of 82% from 2013 to

2018 and to be worth over $6 billion per year by 2018. This paper will

focus on the concept of Li-Fi. Further it will elaborate the history, its need

in technology and its working. Li-Fi is a burning topic in research and

technology. Further the pros and cons of this new technology would also

be talked. Applications of Li-Fi will also be discussed. A comparison of

Li-Fi with Wi-Fi will be made.

KEYWORDS: Li-Fi, LEDs, Wi-Fi and VLC.





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I. INTRODUCTION

Li-Fi or Light Fidelity [1] is an innovative idea in IT that aims at eventually replacing radio

frequency wireless signals with those that come from light sources. This type of technology has

the potential to introduce vastly improved wireless services. Li-Fi is increasingly being used to

refer to the use of Visible Light Communication (VLC) technology [2].

Whether you are using wireless internet, you have probably gotten frustrated at the slow speeds

you face when more than one device is tapped into the network. As more people and their

many devices access wireless internet, clogged radio waves are going to make it increasingly

difficult to latch onto a reliable signal. What if we could use other waves?

One German physicist, Dr. Harald Haas, has come up with a solution he calls “Data through

Illumination”- by sending data through an LED light bulb that varies in intensity faster than the

human eye can follow. Haas says his invention, which he calls D-Light, can produce data rates

faster than 10 megabits per second, which is speedier than your average broadband connection.

He envisions a future where data is transmitted through the light in a room.

Li-Fi refers to a type of visible light communication technology [3] that delivers a networked,

mobile, high-speed communication solution in a similar manner to Wi-Fi. By adding a

microchip to an LED bulb to control on and off switching, the data will flow as binary code: an

on LED is a logical "1" while when off it is a logical "0". Light-emitting diodes are switched

on and off much faster, which makes the light source appear to be continuous.

II. RESEARCH METHODOLOGY USED

A. Objectives Of The Study

To know about Li-Fi Technology, its history and its need.

To know about the various components and working of Li-Fi.

To learn about the advantages, disadvantages and applications of Li-Fi.

To compare Li-Fi with Wi-Fi.

B. Research Design

The research is Literature Based research. This paper involves a comprehensive study of the

earlier work done in this area by reviewers. The major purpose of this research is to know

briefly about the Li-Fi Technology, its components, working, advantages, disadvantages and

applications. Another aim of this research is to compare the Li-Fi with Wi-Fi.





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C. Data Collection

Secondary data is used for the study. Data is collected from the secondary sources like Web-

Resources, and various research papers based upon the Li-Fi technology.

III. HISTORY OF LI-FI

Professor Harald Haas, from the University of Edinburgh in the UK, is widely recognized as

the original founder of Li-Fi. He coined the term Li-Fi [4] and is Chair of Mobile

Communications at the University of Edinburgh and co-founder of pure Li-Fi.

The D-Light project at Edinburgh's Institute for Digital Communications was funded from

January 2010 to January 2012. Haas promoted this technology in his 2011 TED Global talk.

Pure Li-Fi, formerly pure VLC, is an original equipment manufacturer (OEM) firm set up to

commercialize Li-Fi products for integration with existing LED-lighting systems.

In October 2011, companies and industry groups formed the Li-Fi Consortium, to promote

high-speed optical wireless systems and to overcome the limited amount of radio-based

wireless spectrum available by exploiting a completely different part of the electromagnetic

spectrum.

VLC technology was exhibited in 2012 using Li-Fi. By August 2013, data rates of over 1.6

Gbit/s were demonstrated over a single color LED. In September 2013, a press release said that

Li-Fi, or VLC systems in general, do not require line-of-sight conditions. In October 2013, it

was reported Chinese manufacturers were working on Li-Fi development kits.

IV. NEED OF Li-Fi [5]

There are many situations in which people get frustrated with the dull performance signals of

Wi-Fi at a place with many network connections in seminars, conferences etc. Li-Fi fulfills

these needs [6].

Most of us are familiar with Wi-Fi (Wireless Fidelity), which uses 2.4-5 GHz RF to deliver

wireless Internet access around our homes, schools, offices and in public places. But like most

technologies, it has its limitations.

A. Wi-Fi Disadvantages [7]

The use of Wi-Fi band that is 2.4 GHz does not require a license in most countries

provided that is stays below limit of 100mW and one accepts interference from other

sources; including interference which causes the users devices to no longer function.





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The spectrum assignments and operational limitations are not consistent worldwide.

Power consumption is fairly high, making the battery life and heat a concern to some

users.

Wi-Fi networks have limited range. A typical Wi-Fi home router might have a range of

45m (150ft) indoors and 90m (300ft) outdoors. Ranges may also vary as Wi-Fi is no

exception to the physics of radio wave propagation with frequency band.

The most common wireless encryption standard, wired equivalent privacy or WEP has

been shown to be breakable even when it has been correctly configured.

B. Other Problems [8] Which Are Associated With The Wi-Fi Are:

Bandwidth is typically limited to 50-100 megabits per second (Mbps) today using the

IEEE802.11n standard.

It works fine with many of the internet connections. But it is unable to deliver the High

Definition Movies, music libraries or video games.

With the recent increase in the use of cloud computing (where you store your

information on certain web server & not on your local disk), Wi-Fi is not going to be

useful in the future as it will not be able to cater to the need of the increasing bandwidth

& speed.

C. Other Problems with the Radio Spectrum

1. Capacity:

Less bandwidth compared to other spectrums.

Insufficient spectrum for increasing data.

2. Efficiency:

Millions of base stations consume huge amount of energy.

3. Availability:

Available within the range of Base Stations.

Unavailable in aircrafts.

4. Security:

Less secure.

It passes through walls.

V. CONSTRUCTION AND WORKING OF Li-Fi TECHNOLOGY

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 to vary at extremely

high speeds. This property of optical current is used in Li-Fi setup [9].





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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.

Working of Li –Fi [10] is shown in fig. 1. An overhead lamp fitted with an LED with signal

processing technology streams data embedded in its beam at ultra high speeds to the

photodiodes. A receiver dongle than converts the tiny changes in amplitude into an electrical

signal, which is then converted back into a data stream & transmitted to a computer or mobile

device.

Figure 1: Working of Li-Fi Technology

Figure 2: shows the Major Components of Li-Fi Technology.

Figure 2: Components of Li-Fi Technology

Fig. 3 shows brief connection of internet with LED and information retrieved on the computer.

One LED transfers data at a slower rate [11], so millions of LEDs with one micron size are

installed in the bulb. The reduction of size of LEDs does not decrease its capability to transfer

data or intensity; on the opposite it increases the efficiency of one light bulb to transmit the

data at unexpectedly higher rates.





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Figure 3: Connection between LED and a Computer

Replace the IR LED with a Light Box containing a large LED array. This system, fig. 4 is

capable of sending thousands of such streams at very fast rate.

Figure 4: Replacing IR LED with a Light Box containing a large LED array

VI. ADVANTAGES OF Li-Fi

Li-Fi offers a number of key benefits [12] over Wi-Fi

A. CAPACITY

Bandwidth: The visible light spectrum is plentiful (10,000 more than RF spectrum),

unlicensed and free to use.

Data Density: Li-Fi can achieve about 1000 times the data density of Wi-Fi because

visible light can be well contained in a tight illumination area whereas RF tends to

spread out and cause interference.

High Speed: High data rates can be achieved due to low interference and high device

bandwidths.





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B. EFFICIENCY

Low Cost: This Technology requires fewer components than radio technology.

Energy: LED illumination is already efficient and the data transmission requires

negligible additional power.

Environment: RF transmission and propagation in water is extremely difficult but Li-

Fi works well in this environment.

C. SAFETY

Safe: There are no known safety or health concerns for this technology.

Non-hazardous: The transmission of light avoids the use of radio frequencies which

can dangerously interfere with electronic circuitry.

D. SECURITY

Containment: It is difficult to eavesdrop on Li-Fi signals since the signal is confined to

a closely defined illumination area and will not travel through walls.

Control: Data may be directed from one device to another and the user can see where

the data is going; there is no need for additional security such as pairing for RF

interconnections such as Bluetooth.

VII. CHALLENGES FOR Li-Fi

Apart from many advantages over Wi-Fi, Li-Fi technology is experiencing some challenges

[13, 14].

Artificial light cannot penetrate into walls and other opaque materials. So a Li-Fi

enabled end device will never be as fast and handy as a Wi-Fi enabled device in the

open air.

Data transmission is easily blocked by somebody simply walking in front of LED

source.

It only works in direct line of sight.

Wi-Fi Technology is still needed as you can’t have a light bulb that provides data to a

high-speed moving object or to provide data in a remote area where there are trees and

walls and obstacles behind [15].

VIII. APPLICATIONS OF Li-Fi

There are many applications [16] for Li-Fi. These include:





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A. HEALTHCARE SECTOR

This technology can be implemented in hospitals (fig.5) where usage of Wi-Fi is unsafe.

Operating rooms do not allow WI-FI due to radiation concerns, and there is also that a whole

lack of dedicated spectrum. Li-Fi solves both problems: lights are the most glaring fixtures in

the room; And Li-Fi also has 10,000 times the spectrum of Wi-Fi.

Figure 5: Light inside an operation theatre

B. SMARTER POWER PLANTS

Wi-Fi and many other radiation types are bad for sensitive areas like those surrounding power

plants [16]. Li-Fi could offer safe, abundant connectivity for all areas of these sensitive

locations.

C. SMART LIGHTING

Any private or public lighting including street lamps can be used to provide Li-Fi hotspots and

the same communications and sensor infrastructure can be used to monitor and control lighting

and data.

D. ALL INFORMATION UNDER A STREET LIGHT

How about a dinner reservation on the night of your anniversary and you need internet access

but struck in traffic. You just need to put your phone under a street light and book a table at

your favorite restaurant. Don’t forget with Li-Fi, if there’s light, you’re online. Thus Li-Fi

could provide cheap high-speed Web access to every street corner.





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Fig.6 Li-Fi Potential under a Street Light

Fig. 7 Li-Fi Potential inside an airplane

E. ROAD SAFETY AND TRAFFIC MANAGEMENT

Li-Fi can be used for communication between the LED lights of vehicles so as to avoid

collision. It can also be implemented in the traffic lights for vehicle to roadside communication

to update vehicular traffic information.

F. HAZARDOUS ENVIRONMENTS

Li-Fi provides a safe alternative to electromagnetic interference from radio frequency

communications in environments such as mines and petrochemical plants.





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G. SMARTER AIRLINES

To be playing around radio waves on an airplane is a security issue and so passengers are

requested to switch off their electrical devices during a flight. Li-Fi can be used to reduce

weight and cabling and add flexibility to seating layouts in aircraft passenger cabins where

LED lights are already deployed.

H. MOBILE CONNECTIVITY

Laptops, smart phones, tablets and other mobile devices can interconnect directly using Li-Fi.

Short range links give very high data rates and also provides security.

I. UNDERWATER COMMUNICATIONS

Due to strong signal absorption in water, RF use is impractical. Acoustic waves have extremely

low bandwidth and disturb marine life. Li-Fi provides a solution for short-range

communications.

J. TOYS

Many toys incorporate LED lights and can be used to enable low-cost communication between

interactive toys.

IX. COMPARISON OF Li-Fi TECHNOLOGY WITH Wi-Fi

The Comparison [10] of Li-Fi and Wi-Fi is shown in Table 1.

Sr.

No.

Wi-Fi Li-Fi

1 Wi-Fi transmits data over the radio

waves.

Li-Fi transmits data over the visible light &

some

2 It can penetrate solids. It cannot penetrate solids.

3 Data transfer rate is much slower. Data transfer rate is very fast.

4 In Wi-Fi signals there is lot of noise

when the number of Wi-Fi network

increase in a particular area.

Such type of problem is not faced by the Li-Fi.

5 Expensive in comparison to Li-Fi

because its uses radio spectrum

Cheaper than Wi-Fi because free band doesn’t

need license and it uses light

6 Operating Frequency is 2.4 GHZ Operating Frequency is Hundreds of Tera Hz

7 Radio frequency spectrum range is

less than visible light spectrum

Visible light spectrum has 10,000 time broad

spectrum in comparison to radio frequency

Table 1: Comparison of Li-Fi and Wi-Fi Technologies





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X. CONCLUSION

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

congested, 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.

Li-Fi has great potential in the field of wireless data transmission. It is a promising alternative

to conventional methods of wireless communications that use radio waves as data carrier.

Many enhancements can be made to the existing technology. For example, encoding and

decoding can be implemented directly in the transmitter and receiver part of the circuit. This

would reduce error in transmission. Also, by using fast-switching LEDs, data transmission

rates can be further enhanced.

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.

We can be sure that the future for Li-Fi is bright. Li-Fi consortium believes it is possible to

achieve more than 10Gbps, theoretically allowing a high definition film to be downloaded in

30 seconds.

XI. REFERENCES

1. Definition of Li-Fi from <http://www.techopedia.com/definition/29638/lifi-led>

2. Introduction to Li-Fi Technology from <http://compnetworking.about.com/b/2012/10

/03/what-is-li-fi.htm>

3. Li-Fi Technology (Internet through light bulbs) from <http://www.jagranjosh.com/current -

affairs/chinese-scientists-developed-lifi-technology-internet-through-lightbulbs-

1382074886-1>

4. History of Li-Fi retrieved from <http://en.wikipedia.org/wiki/Li-Fi> retrieved on March 29,

2014.

5. Need of Li-Fi from<http://electronicsforu.com/electronicsforu/circuitarchives/view article

.asp?sno=778&title%20=%20Li-Fi%3A+A+New+Paradigm+in+Wireless+

Communication &id=12042&article_type=8&b_type=new>





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6. Navyatha, N. & Prathyusha, T.M. (2013), Li-Fi (Light fidelity)-LED Based Alternative ,

International Journal of Scientific & Engineering Research, Vol 4, Issue 5, ISSN 2229-

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7. Wi-Fi Disadvantages from <http://www.bwif.org/wifi_disadvantages.html>

8. Problems with Wi-Fi from <http://www.erewise.com/current-affairs/li-fi-technology-light-

fidelity_art53046b047a994.html#.Uz0KpqLqT4g>

9. Working of Li-Fi Technology from <http://www.seminarsonly.com/computer

%20science/Li-Fi-Technology.php> retrieved on April 13, 2014

10. Goyal, M. & Saproo, D. (2013), New Epoch of Wireless Communication: Light Fidelity,

International Journal of Innovative Research in Computer and Communication Engineering

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technology-in-wireless-communication-revathi-ganesan> retrieved on April 17, 2014.

12. Sonnad, M.A & Gopan, A. (2013), Recent Advancements In Li-Fi Technology,

International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084

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Journal of Research & Development in Technology and Management Science, Volume 21,

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14. Sharma, R. & Sanganal, A. (2013), Li-Fi Technology Transmission of data through light,

International Journal of Computer Technology& Applications, Vol 5,150-154.

15. Nivrutti, V. & Ramchandra, R. (2013), Light-Fidelity: A Reconnaissance of Future

Technology International Journal of Advanced Research in Computer Science and

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International Journal of Research & Development in Technology