Li-Fi: Internet Through Light - Academic · PDF fileISSN 2347 27 Shubham Panjwani, Abhinav,...

27 Shubham Panjwani, Abhinav, AishwaryaVarshney

International Journal of Computer & Mathematical Sciences

IJCMS

ISSN 2347 – 8527

Volume 6, Issue 3

March 2017

ABSTRACT

Li-Fi stands for Light Fidelity. Li-Fi is a visible light

communication technology developed by a team of scientist

including Dr. Gordon Povey, Prof. Harald Hass and Dr.

Mostafa Afghani at the university of EdinBurgh. Li-Fi is a

Visible Light Communications (VLC) system running wireless

communications travelling at very high speeds. Li-Fi and Wi-

Fi are quite similar as both transmit data electromagnetically.

However, Wi-Fi uses radio waves while Li-Fi runs on visible

light. Li-Fi uses common household LED (light emitting

diodes) lightbulbs to enable data transfer, boasting speeds of

up to 224 gigabits per second. Li-Fi provides better

bandwidth, efficiency, availability and security than Wi-Fi. Key Words — Li-Fi, Wi-Fi, LED, wireless communication,

photodiode.

I. INTRODUCTION

Li-Fi is a VLC, visible light communication technology,

developed by the team of scientists including professor

Haas at the University of Edinburg and deals with

transfer of data through illumination by taking fiber out

of optics by sending data through a LED light bulb that

varies in the intensity faster than a human eye can

follow. [4] Dr. Haas amazed people by streaming HD

video from a standard LED lamp, at TED Global in July

2011 and thereby coined the term Li-Fi. Li-Fi is now

part of visible light communication (VLC). It can be

very easily explained as, if the LED is ON, you are

transmitting the data means you transmit a digital 1 and

if the LED is OFF you transmit a digital 0, or null, or

simply no data transfer happens. As one can switch them

on and off very frequently one can transmit data easily

because the LEDs intensity is modulated so rapidly that

human eye cannot notice, so the output in form of light

appears constant and hence offering permanent

connectivity. [1]

In simple terms, LI-FI can be thought of as a WI-FI

based on light as it uses light instead of radio waves to

transmit information. Instead of WI-FI modems or

routers, LI-FI uses transceiver-fitted LED lamps that can

be used as a light or for transmission of the data

communication through internet. [5] This technology

uses a visible light communication spectrum and has not

major ill effect as we know that the light is very much

part of our life. Moreover, in this spectrum 10,000 times

more space is available and it also multiplies to 10,000

times more availability as a light bulb and street bulbs

are available already [2].

Figure 1:Li-Fi in real life scenario

Li-Fi can play a major role in relieving the heavy loads

which the current wireless systems face since it adds a

new and unutilized bandwidth of visible light to the

currently available radio waves for data transfer.

[6]Thus, it offers much larger frequency band (300 THz)

compared to that available in RF communications

(300GHz). Also, more data coming through the visible

spectrum could help alleviate concerns that the

electromagnetic waves that come with Wi-Fi could

adversely affect our health. Li-Fi can be the technology

for the future where data for laptops, smart phones, and

tablets will be transmitted through the light in a room.

Security would not be an issue because if you cannot see

the light, you can‘t access the data. As a result, it can be

used in high security military areas where RF

communication is prone to eavesdropping. [3]

II. HOW LI-FI WORKS?

Li-Fi is high speed bidirectional networked and mobile

communication of data using light. Li-Fi comprises of

multiple lightbulbs that form a wireless network. 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

Shubham Panjwani1, Abhinav

2, Aishwarya Varshney

3

1 Student, Department of Computer Science

2Student, Department of Computer Science

3Asst. Professor, Department of Computer Science

1,2,3Modi Institute of Technology, Kota.

Li-Fi: Internet Through Light



IJCMS

ISSN 2347 – 8527

Volume 6, Issue 3

March 2017

current. However, by fast and subtle variations of the

current, the optical output can be made to vary at

extremely high speeds. This very property of optical

current is used in Li-Fi setup. The operational procedure

is very simple-, data from the internet and local network

is used to modulate the intensity of the LED light source

if any undetectable to the human eye. As a comparison,

the lowest frequency at which the lights are modulated is

1MHz and this is 10,000 times higher than the refresh

rate of our computer screens.

The photo detector picks up signal, which is converted

back into a data stream and sent to the client.

The client can communicate through its own LED output

or over the existing network. An overhead lamp fitted

with an LED with signal-processing technology streams

data embedded in its beam at ultra-high speeds to the

photo-detector. A receiver dongle then converts the tiny

changes in amplitude into an electrical signal, which is

then converted back into a data stream and transmitted to

a computer or mobile device.

Light is inherently safe and can be used in places where

radio frequency communication is often deemed

problematic, such as in aircraft cabins or hospitals. So

visible light communication not only has the potential to

solve the problem of lack of spectrum space, but can

also enable novel application. The visible light spectrum

is unused, it's not regulated, and can be used for

communication at very high speeds

Figure 2: Implementation of Li-Fi

III. LIFI V/S WIFI

LIFI claims to be hundred time faster than WIFI. It has

attend speed of 224 gigabits per second in lab test. Li-Fi

is transmission of data using illumination, while Wi-Fi

uses radio spectrum instead of Wi-Fi modem Li-Fi

would use transceiver fitted led lamps that can light a

room as well as transmit and receive information. Wi-Fi

is great for in general wireless coverage within building

and Li-Fi is ideal for high density wireless range

coverage in confined area and relieving radio

interference issue. Li-Fi offers better data defense as

light waves can’t pass through walls, making it

impossible to hack any internal system in high-security

building.

Figure 3: Comparison between Li-Fi and Wi-Fi

TABLE I: Difference between Li-Fi and Wi-fi

As radio waves used by Wi-Fi get more congested and

the demand for faster and more efficient wireless

communication escalates the future is bright for Li-Fi as

reliable, affordable and more secure solutions.

IV. CHALLENGES

Although there are a lot of advantages of LI-FI, there are

still certain challenges which need to be overcome:

Presence of light is essential

Works better with fluorescent light and LED but

very low efficiency with bulb

High installation cost

Light can pass through object

Short range

S.NO PARAMETER Li-Fi Wi-Fi

1 SPEED >1GB/S Around 150 Mb/s

2 Medium of data

transfer

Use light

as carrier

Use radio

spectrum

3 Spectrum range Visible

light has

10000

times

more

Having less

spectrum range

than VLC

4 Cost Cheaper Expensive

5 Network

Topology

Point to

Point

Point to Point

6 Operating

frequency

Hundreds

of Tera

Hz

2.4 GHz



IJCMS

ISSN 2347 – 8527

Volume 6, Issue 3

March 2017

V. ADVANTAGES

In Li-Fi the data is transferred through the light without

depending on the spectrum of light, it may belong to the

invisible, ultraviolet, visible portion of the spectrum. It

provides the speed up to 1Gbps with the exceptional

bandwidth and overcomes the limitations of the Wi-Fi.

Few advantages of it are as follows:

Li-Fi provides 10,000 times wider bandwidth than

the Wi-Fi and the light sources of Li-Fi are already

installed. So, it doesn’t need any well-equipped

equipment and provides good capacity.

The transmission of information through it is very

cheap and affordable due to the low energy

consumption and efficiency of LED bulbs.

Li-Fi doesn’t provide an issue of availability because

in the world there is no scarcity of bulbs and the

only thing is that they need to be replaced by LED’s

for the sending of information or data.

A high rate of transmission of information up to

10Gbps can be succeeded.

It has less maintaining cost and low implementing

cost.

Li-Fi provides high security because the light cannot

travel or enter the walls and due to this the factor of

misuse cannot occur.

The issue of insufficiency can be eradicated because

Li-Fi uses light which is still not used in abundance

.

VI. APPLICATION

At present its applications are beyond imagination but

still if to think about few then they are:

Can be used in places where it is difficult to lay the

optical fiber like hospitals. In operation theatre Li-Fi

can be used for modern medical instruments.

In traffic signals Li-Fi can be used which will

communicate with LED lights of the cars and

accident numbers can be decreased

Thousand and millions of street lamps can be

transferred to Li-Fi Lamps to transfer data.

In aircraft Li-Fi can be used for data transmission.

It can be used in petroleum or chemical plants where

other transmission or frequencies could be

hazardous.

VII. CONCLUSION

The exponential growth in connected devices and data

demands is leading to frequency congestion and that

could make current wireless technology unsustainable in

the long term. Li-Fi can make much greater volumes of

data accessible and securing access is as simple as

pulling the shades.

The future looks bright for Li-Fi. The speed that Li-Fi

can reach, space and spatial limits, the technology will

work well alongside cellular and Wi-Fi technology as an

additional option for connectivity. Li-Fi can be used to

syphon off heavy traffic from cellular and Wi-Fi

network.

Li-Fi is the and on growing technology acting as

component of various other developing and already

invented technology. Since light is the major source of

transmission in this technology it is very advantageous

and implementable in various fields that can’t be done

with Wi-Fi and other technologies.

Hence the future applications of the Li-Fi can be

predicted and extended to different platforms like

education field, medical field, industrial area and many

other fields. The possibilities are numerous and can be

explored further. If this technology can be put into

practical use, every bulb can be something like a Wi-Fi

hotspot to transmit wireless data and we will proceed

towards the cleaner, safer and brighter future.

The concept of Li-Fi is now attracting a great deal of

interest because it offers a genuine and efficient

alternative to radio based wireless systems.

REFERENCES [1] Dinesh Khandal, Sakshi Jain., ―Li-Fi (LightFidelity)-The

future technology In Wireless communication,

International Journal of Information & Computation

Technology ISSN 0974-2239

[2] Jay H. Bhut, Dharmrajsinh N. Parmar, Khushbu V.

MehtaLI-FI Technology – A Visible Light

Communication,International Journal of Engineering

DevelopmentAndResearch ISSN: 2321-9939.

[3] Rahul R. Sharma, Raunak, AkshaySanganal-Li-Fi

TechnologyTransmission of data through light IJCTA

2014,ISSN:2229-6093, Vol 5 (1),150-154.

[4] Vitthal S Saptasagare- Next of Wi-Fi an Future

Technologyin Wireless Networking Li-Fi Using Led Over

InternetofThings, International Journal of Emerging

ResearchinManagement&Technology ISSN: 2278-9359

(Volume-3, Issue-3)(2014).

[5] Shubham Chatterjee, ShalabhAgarwal ,AsokeNath-

Scopeand Challenges in Light Fidelity(LiFi) Technology

inWirelessData Communication , International Journal of

InnovativeResearch in Advanced Engineering (IJIRAE)

ISSN:23492163Issue 6, Volume 2 (June 2015).

[6] RevathiGanesan- Li-Fi Technology in Wireless

Communication, INTERNATIONAL JOURNAL &

MAGAZINE OF ENGINEERING, TECHNOLOGY,

MANAGEMENT AND RESEARCH,ISSN No: 2320-

3706



IJCMS

ISSN 2347 – 8527

Volume 6, Issue 3

March 2017

[7] AnuragSarkar, Prof. ShalabhAgarwal , Dr. AsokeNath-

LiFi Technology: Data Transmission through Visible

Light,International Journal of Advance Research in

ComputerScienceand Management Studies, ISSN: 2321-

7782 Volume 3, Issue 6,

June 2015

[8] AkshitAggarwal -COMPARATIVE STUDY : LI-FI V/S

WIFI , International Journal of Research & Development

inTechnology and Management Science –Kailash Volume

-21|Issue 1 | ISBN - 978-1-63102-445-0 | March 2014

R.Karthika, S.Balakrishnan- Wireless Communication

usingLi-Fi Technology, SSRG International Journal of

Electronicsand Communication Engineering (SSRG-

IJECE) volume 2 Issue

3 March 2015 ISSN: 2348

[9] Dr.Y.P.Singh, AbhishekHaridas, Critical Technical

Aspectand Extensive Research Study of the Light Fidelity

–aFutureCommunication), International Journal of IT,

EngineeringandApplied Sciences Research (IJIEASR)

Volume2,No.9,September 2013 , ISSN: 2319-4413

Li-Fi: Internet Through Light - Academic · PDF fileISSN 2347 27 Shubham Panjwani, Abhinav,...

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