Overview of Li-Fi Technology

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072
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Overview of Li-Fi Technology
Sushma L.Wakchaure, Shailaja D.Pawar, Vijay V.Thitme, Bipin B.Shinde
Amrutvahini Polytechnic, Sangamner
Professor, Dept. of Computer Engineering, Amrutvahini Polytechnic College, Maharashtra, India.
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Abstract - Li-Fi that is light fidelity is one of the future
technologies in wireless communication sector. It is a
bidirectional, with a very high speed and is a fully networked
communication which is wireless technology similar to Wi-Fi.
In the present era, Wi-Fi is the most trending domain. As
internet users almost double every year, there is an enormous
load on radio spectrum that leads to congestion. To get better
bandwidth, efficiency and speed, a new technology Li-Fi has
evolved.. Li-Fi can be simply put to be Wi-Fi but instead of
radio waves light is used as a medium. Here, data is
transmitted using light whose intensity varies faster than
human eye to capture. Instead of usingmodems, Li-Fi usesLED
bulbs with transceiver. Data transmission in Li-Fi isabout100
times faster than Wi-Fi. Here, in thispaperweexploretheneed
for Li-Fi. Li-Fi technology, proposedbytheGermanScientist —
Harald Haas, Harald Haas proposed the technology that
transmits the data through illumination .Li-Fi is ideal for high
speed wireless data transmission in confined area. Li-Fi
provides higher bandwidth, efficiency, availabilityandsecurity
than Wi-Fi and has already achieved high speed in the lab. we
can implement this system public internet access through
street lamps to auto -piloted cars that communicate through
their headlights. As the speed of light is higher hence the data
transmission speed is so much faster that the existing system.
In the future we can implement this technology for fast data
access for the laptops, smart phones, and tablets will be
transmitted through the light in a room
Key Words: Wireless-Fidelity (Wi-Fi), Light-Fidelity (Li-
Fi), Light Emitting Diode (LED).
1. INTRODUCTION
Harald Haas was developed LI-FI and promoted LI-FI in his
2011 TED Global talk by giving Presentation of an LED light
bulb to transmit a data with the speed 10 times more faster.
As the speed of light is very high so the data transmission
speed via the light is also high. Transfer of data from one
place to another is one of the most important day -to-day
activities. When the multiple devices are connected to the
current wireless networks thatconnectustothe internet are
very slow. As the number of devices increasing the internet
access, the fixed bandwidth which is availablemakesitmore
and more difficult to utilize high data transfer rates and
connect to a network. But, radio waves are just a small part
of the spectrum available for data transfer. A solution to this
problem is by the use of the proposed system. Li-Fi is
transmission of data through light by sending data through
an LED bulb that varies in intensity faster than the human
eye can follow and the faster data transmission speed. Li-Fi
is the new technology has used to label the fast and cheap
wireless communication system, which is the next optical
version of Wi-Fi.
Fig1:Symbol of Li-Fi & Wi-fi
Li-Fi uses light spectrum that send via LED Bulb instead of
Gigahertz radio waves for data transfer. This technology
communicate with the help of visible light communication
spectrum and has no side effect as we know the light is very
much part of our life and so much faster. In this spectrum
10,000 times more space is available and also more
availability as a LED light bulb and street light are available
already. There are some commonly used examples of
wireless networks like- traffic control systems, Bluetooth,
infrared and ultrasonic remote control devices, VHF radios,
professional LMR, SMR, Two way radio including FRS, GPS,
cordless telephone, satellite TV etc Wi-Fi connection within
the Building and around the 10-100 meter range to connect
our Laptops, P.C., palmtops etc. The currentpaperdealswith
the visible light communicationwhichmayutilizea wideand
fast data rate like 500MBPS. Study made comparison
between WI-Fi, Wimax, LI-Fi and other important
parameters of the communication process. Li-Fi can be the
future technology for where data for laptops, PC, smart
phones, and tablets will be transmitted through thelightina
room. It is more secure because if you can‘t see the light, you
can‘t access the data. As a result, it can be implemented in
high security areas like military where RF communicationis
prone to eavesdropping. INTRODUCTION Light–Fidelity
technology came into existence in 2011.Harald Haas was
coined the term LI-FI and promoted LI-FI. Li-Fi is used for
enjoying high data transfer rates. Li-Fi is a fast and cheap
optical version of Wi-Fi. It is based on Visible Light
Communication (VLC) which is used to transmit data using
the spectrum of visible light. In Wi-Fi use radio spectrum to
transmit data but due to shortage of radio frequencies and
risk of interference it having some limitation. Li-Fi uses
visible light instead of Gigahertz radio waves for data
transfer. VLC is a data communication medium, which uses

visible light between 400 THz and 800 THz as optical carrier
for data transmission and illumination. Li-Fi is the wireless
communication system which transmission of data through
illumination. Li-Fi is transmission of data through an LED
light bulb that varies in intensity faster than the human eye
can follow. Li-Fi is a framework for providing new
capabilities to current and future services, applications and
end users.
Fig2: Block Diagram of Li-Fi Technology
2) HISTORY AND FUTURE OF LI-FI
The technology underpinning Li-Fi was pioneered by
German Physicist HaraldHass,currentlybasedatniversityof
Edinburgh in UK. Haas coined the term Li-Fi(Light Fidelity)
in 2011 in the context of a talk presenting the new
technology at the TED (Technology Entertainment and
Design) Global conference.[7][17] The wordquicklyentered
common parlance as an instantly recognizablealternative to
Wi-Fi. Both terms are examples of abbreviations linguists
sometimes describe as clipped forms( i.e. Wi-Fi=wireless
fidelity, Li-Fi= light fidelity).[15]Haas’s research project,
originally known as D-light(short for Data Light), is now set
to launch a prototype Li-Fi application under the name of
newly-formed company VLC(Visible Light Communication)
Ltd., which was setup to commercialize the technology.[16]
The Li-Fi technology can be used for various purposes, it
matters the data transmission through LEDs thus all the
screens which illuminate light can be served as a platform
for data communication. The screen of the mobile phone,
television, bulbs can act as a source of light. On the other
hand, the receiving platform, the photo detector can be
replaced by a camera in mobile phone for scanning and
retrieving data. Its other applications are Li-fi for desktops,
smartcard Li-fi, Li-fi for schools, hospitals, Li-fi in cities,
smart guides, museums, hotels, fairgrounds, events indoor
and LBS(Location-based Services), access control and
identification crisis, malls, airport and dangerous
environments like thermal power plants.[8][11].
Fig3: Construction of Li-Fi
3. LITERATURE SURVEY
Using a standard white-light LED, researchers at the
Heinrich Hertz Institute in Berlin, Germany, have reached
data rates of over 500 megabytes per second [1]. Li-Fi
Consortium was formed in October2011 by a group of
companies and industry groups to promote high-speed
optical wireless systems and overcome the limited amount
of radio based wireless spectrum. According to the Li-Fi
Consortium, it is possible to achieve more than 10 Gbps of
speed, theoretically which wouldallowa high-definitionfilm
to be downloaded in just 30 seconds [2]. Researchers at the
University of Strathclyde in Scotland have begun the task of
bringing High-speed, ubiquitous, Li-Fi technology to market
WANG Jia-Yuan, ZOU Nian-Yu, WANG Dong, IRIEKentaro,
IHA Zensei, NAMIHIRA Yoshinori .The Journal of China
Universities of Posts and Telecommunications.In thispaper,
the illumination of the receiving surface for different
distances between the LED and photodiode receiver was
tested. It was found that with the increase incommunication
distance, the illumination sharply reduced [3].
4. PRINCIPLE
Light Fidelity or Li-Fi is a Visible Light Communications
(VLC) system running wirelesscommunicationstravellingat
very high speeds. Li-Fi uses common household LED (light
emitting diodes) light bulbs to enable data transfer, boasting
speeds of up to 224 gigabits per second. The basic idea
behind this communication scheme is transmission of ‘Data
through illumination’ .Heart of Li-Fi technology is high
brightness LED’s. The on-off activity of LEDs enables a kind
of data transmission using binary codes mode however the
human eye cannot perceive this change andtheLEDsappear
to have a constant intensity.

Fig4: Working Principle of Li-Fi
5. COMPARISON BETWEEN LI-FI AND WI-FI
Li-Fi name is used to describe VLC technology whichapplied
to achieve high-speed wireless communication. It acquired
this name because of the similarity to Wi-Fi which works
well within buildings for general wirelesscoverage while the
Li-Fi is an ideal option for high-density wireless data
coverage. Table 1 shows a comparison of transfer speed and
data density of various wireless technologies. It seems that
Wi-Fi technology offers high data rate, about 150 Mbps,
comparing with others current wireless technologies.
Fig5: Comparison between Li-Fi and Wi-Fi
6. ADVANTAGES OF LI-FI
Li-Fi technology is based on using a light source for
transferring data and no matter which part of the spectrum,
visible or invisible, is used [7]. It supports the user with
more than sufficient communication speed for downloading
movies, music, games and all in very less time. In addition, it
removes the limitations which have been put on the Wi-Fi
users. a) Capacity: light has 10,000 times wider bandwidth
than radio wave which gives the Li-Fi bettercapacity[11].b)
Efficiency: Li-Fi is highly efficient because of the LED lights
consume low energy [9]. c) Availability: they are billions of
light bulbs worldwide which just need to be replaced with
proper transmission of data LEDs. Possibly in the future,
every street light could be free hotspot [3]. d) Security:Light
waves are more secure than electric waves because they
cannot penetrate through walls. Therefore, the Li-Fi signal
can't be intercepted and misused. e) Utilization: Li-Fi can be
used in places where Wi-Fi cannot be used or barred suchas
under water, aircraft cabins and nuclear power plant. f)
Safty: unlike radio frequencies, Li-Fi cannot penetrate
human body [12].
7. LIMITATION OF LI-FI
Li-Fi technology like any other technology has some
limitations which enumerated below: a) Themajordemerits
of Li-Fi is that the artificial light, data transmission, can be
obstructed by an opaque material, then the signal will becut
out. b) It works only if there is line of sight between
transmitter and receiver [13]. c) Reliability is another
shortcoming because of the interface from external light
sources such as normal bulbs and sunlight [1, 5]. d) The
major challenge is how the receiver will transmit data back
to the transmitter [5]. e) Coverage area is as another issue
because Li-Fi using very high frequencies, 400-800THz,
which limits the coverage area to very short distance
(practically, 500Mbps over four feet and 120Mbps over 65
feet) [2].
8. LI-FI APPLICATIONS
There are numerous applications of Li-Fi technology, from
providing internet access through street lamps to allowing
auto-piloted cars communicate through their headlights[7].
Some of the future applications of Li-Fi technology are as
follows:
a) Medical Applications: Li-Fi technology can be
implemented in hospitals where using Wi-Fi is unsafedueto
radiation concerns. Wi-Fi signal is banned inside operation
theatres because it might block signal for monitoring
equipment like MRI equipment. However, Li-Fi can be
beneficial for robotic surgeries [7, 12].
b) Road Safety and Traffic Management: vehicles can be
communicates using Li-Fi through the LED lights to avoid

collation and. Therefore, occurrences of accidents can be
reduced [2].
c) Smart lighting: any light source, private or public like
street lamps, can be used for providing Li-Fi hotspot as well
as for lighting.
d) Aviation: Aircraft cabins already have LED lights which
can be used to provide high-speed Internet access [14].
e) Underwater communication: Li-Fi can work underwater
where Wi-Fi fails completely. Using Li-Fi in underwater
ROVs (Remotely Operation Vehicles) will allow them to
communicate with each other using light source instead of
using cables. Also, divers can be communicates using their
headlamps [7].Li-Fi emits no electromagnetic interference
and so does not interfere with medical instruments, not is it
interfered with by MRI scanners as its frequency is in visible
spectrum as shown in below diagram.
Fig6: Hospital and Healthcare application Li-Fi Technology
9. RECENT ADVANCEMENTS IN LI-FI
The Li-Fi Consortium emphasizes that it is possible to get
speeds greater than 10 GHz using Li-Fi technology [1].Inthe
beginning, over 500 megabytes per second (data rate) was
achieved by researchers at the Heinrich Hertz Institute in
Berlin in Germany using a stander white-light LED [1, 15].
Then, Harald Hass’ groups with researchers from
universities of Cambridge, St, Andrews, Oxford and
Strathclyde have used an arrayofLEDswithmultiplecolours
to get high band width linking over few meters [1, 7].
Recently, Li-Fi Consortium created a newLi-Fisystemwhich
could receive and send data at rates110Mbpsusingred, blue
and green LEDs as both emitter and photodiodes for
detecting light. They developedtheirsystemtotransmitdata
at the speed of 1.1Gbps over 10 meters [1]. Sisoft (Mexican
company) and researchers from AutonomousTechnological
Institute of Mexico (ITAM) claimed that they have used LED
lamps for transmitting data in one direction, with data rate
10Gbps, while simultaneously lighting the room [7]. More
recently, 224 Gbps bi-directional speed over 3 meters was
achieved by University of Oxford researchers using IR
technology. This speed will allow 18 movies, 1.5 GB each, to
be download in a single second [1]. Finally, researchers at
Leeds University achieved 20 Gbps, indoor VLC using laser
diodes (LDs) [16]. Scope of Li-Fi Technology Industry
For: Transparency Market Research: Some of the leading
enterprises operating in the Li-Fi market include Philips,
LVX, PureLifi, GE, Oledcomm and others. The majority of
these market players are focusing on strategic
collaborations, mergers, and acquisitions to gain a
competitive edge. For instance, GE recently collaborated
with Qualcomm to merge big data and lighting to transform
the retail experience. In 2015, LVX partnered with NASA to
introduce products for space missions and design new
applications for VLC.
10. LIFI OVER OTHER TECHNOLOGIES
LiFi can be used at places where other waves like radio
waves or sound waves have limitations. LiFi also provides
additional features like high data rates and security.
Applications of LiFi include:
 Cellular Communication: LiFi can provide higher data rate
(especially high downlink) and security in comparison to
WiFi for short distances.
 Hospitals:LiFi can be integrated into medical devices and
can be used in hospitals where WiFi is banned as it emits
electromagnetic interferences withmedical instruments and
MRI Scanners.
 Aviation: LiFi can use LED lights which are already
deployed in airplanes. Using LEDs for communication can
reduce heavy cabling and add flexibility to seating layoutsin
passenger cabins.
 Underwater Communications: Radio waves are quickly
absorbed in water and acoustic waves disturb marine life,
but LiFi using light signals can be used as an alternative to
this problem for short-range underwater communications.
 Vehicle & Traffic management: LEDs can be used in head-
lights, tail-lights, street lamps, signage and traffic signals for
vehicle-to-vehicle and vehicle-to-roadside communications.
This can avoid road accidents and make traffic control more
intelligent.
 Hazardous Environments: LiFi uses light signals for
communications, so it can provide a safe alternative to
electromagnetic interferences from radio frequency
communications in environments such as mines and
petrochemical plants.
 RF Spectrum relief: Due to excessive usage of radio waves
for communication, we may face a shortage of

radiofrequency bandwidth.LiFicanbeusedasanalternative
to radio waves for short distance communication.
 RF Avoidance: Some people claims that radio frequency
used in mobile and WiFi communication can cause brain
cancer. So, LiFi is a good solution to this problem.
CONCLUSIONS
Li-Fi has great potential in wireless data transmission field.
It offers tremendous scope for future innovation and
research instead of it still in its incipient stages. Every bulb
can be used as a Wi-Fi hotspot for transmittingwirelessdata
if Li-Fi technology put into practical use. This technique will
help to create the cleaner, safer, greener and a resplendent
future. Additionally, it will allow internet connection where
Wi-Fi is banned in some places such as aircraft and
operation theatres. However, one of theshortcomingsisthat
it works in direct line of sight only. Li-Fi is the future
technology of data transmission. Since it is easy to generate
light waves, it is very advantageous and easily
implementable in variousfields.Hencethefutureapplication
can be extended to the various fields like Traffic.
ACKNOWLEDGEMENT
The authors would like to thank the reviewers for their
comments which helped to improve the presentation of the
paper.
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