Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission. It can provide higher speeds than Wi-Fi and has a number of advantages including increased capacity, energy efficiency, and enhanced security compared to traditional radio-frequency wireless networks. Li-Fi is a subset of visible light communication (VLC) and works by modulating the intensity of light from an LED to transmit data to a photodetector. This allows bidirectional communication in a similar manner to Wi-Fi networks.

1. LI-FILI-FI

2. What is Li-Fi?
 The term Li-Fi was coined by pure LiFi CSO,
Professor Herald Haas, and refers to light based
communications technology that delivers a high-
speed, bidirectional networked, mobile
communications in a similar manner as Wi-Fi. Li-
Fi can be used to off-load data from existing Wi-Fi
networks, implementations may be used to
provide capacity for the greater downlink demand
such that existing wireless or wired network
infrastructure may be used in a complementary
fashion.

3. What is Li-Fi?
LiFi is the use of the visible light portion of the
electromagnetic spectrum to transmit information
at very high speeds. This is in contrast to
established forms of wireless communication such
as Wi-Fi which use traditional radio frequency
(RF) signals to transmit data.
With LiFi, data is transmitted by modulating the
intensity of the light, which is then received by a
photo-sensitive detector, and the light signal is
demodulated into electronic form. This
modulation is performed in such a way that it is
not perceptible to the human eye.

5. What is Li-FiWhat is 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 and is Chair of Mobile
Communications at the University of Edinburgh and co-
founder of pure LiFi.
 The general term visible light communication (VLC)
includes any use of the visible light portion of the
electromagnetic spectrum to transmit information. 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 and helped start a company to market it
Pure LiFi, formerly purely, is an original equipment
manufacturer (OEM) firm set up to commercialize Li-Fi
products for integration with existing LED-lighting
systems.

6.  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.
 A number of companies offer uni-directional VLC products,
which is not the same as Li-Fi VLC technology was exhibited in
2012 using Li-Fi . By August 2013, data rates of over 1.6 G/bits
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
 In April 2014, the Russian company Stins Coman announced the
development of a Li-Fi wireless local network called Beam
Caster. Their current module transfers data at 1.25 gigabytes
per second but they foresee boosting speeds up to 5 GB/second
in the near future. In 2014 a new record was established by
Sisoft (a Mexican company) that was able to transfer data at
speeds of up to 10Gbps across a light spectrum emitted by LED
lamps.

7. Optical Communication:
LiFi is a category of Optical Wireless
Communications (OWC). OWC includes infra-red
and ultra-violet communications as well as visible
light. However, LiFi is unique in that the same
visible light energy used for illumination may also
be used for communication.
It is also known as optical telecommunication,
is communication at a distance using light to carry
information. It can be performed visually or by
using electronic devices. The earliest basic forms of
optical communication date back several millennia,
while the earliest electrical device created to do so
was the photo phone , invented in 1880.

8.  An optical communication system uses
a transmitter, which encodes a message into an
optical signal, a channel , which carries the signal
to its destination, and a receiver, which
reproduces the message from the received optical
signal
 Optical fiber is the most common type of channel
for optical communications. The transmitters in
optical fiber links are generally light-emitting
diodes (LEDs) or laser diodes. Infrared light,
rather than visible light is used more commonly,
because optical fibers transmit infrared
wavelengths with less attenuation and dispersion

9. Optical wireless communications
 It is a form of optical communication in which
unguided visible, infrared(IR) ,
or ultraviolet(UV) light is used to carry a signal.
 OWC systems operating in the visible band (390–
750 nm) are commonly referred to as visible light
communication (VLC). VLC systems take
advantage of light emitting diodes (LEDs) which
can be pulsed at very high speeds without
noticeable effect on the lighting output and
human eye. VLC can be possibly used in a wide
range of applications including wireless local area
networks, wireless personal area networks and
vehicular networks among others.

10. The proliferation of wireless
communications stands out as one
of the most significant phenomena
in the history of technology.
Wireless technologies have
become essential much more
quickly during the last four
decades and they will be a key
element of society progress for
the foreseeable future. The
proliferation of wireless
communications stands out as one
of the most significant phenomena
in the history of technology.
Wireless technologies have
become essential much more
quickly during the last four
decades and they will be a key
element of society progress for
the foreseeable future.

11. Transmission Range OWC
 Ultra-short range OWC
 Short range OWC
 Medium range OWC
 Long range OWC
 Ultra-long range OWC

12. Visible Light Communication
Visible light is only a small portion of the electromagnetic
spectrum.
The technology uses
fluorescent lamps
(ordinary lamps, not special
communications devices)
to transmit signals at
10 k/bits, or LED for up to
500 Mbit/s.
Low rate data transmissions
at 1 and 2 kilometers (0.6 and 1.2 mi) were
demonstrated. RONJA achieves full Ethernet speed (10 Mbit/s)
over the same distance thanks to larger optics and more
powerful LEDs.

13. How does LiFi work?

14.  Li-Fi is a Visible Light Communications (VLC) system for
data transmission. A simple VLC system has two qualifying
components:
1) At least one device with a photodiode able to receive
light signals and
2) A light source equipped with a signal processing unit.
 Li-Fi (Light Fidelity) is a bidirectional, high speed and fully
networked wireless communication technology similar to
Wi-Fi. Coined by Prof. Harald Haas, Li-Fi is a subset of
optical wireless communications (OWC) and can be a
complement to RF communication (Wi-Fi or Cellular
network), or a replacement in contexts of data
broadcasting. It is so far measured to be about 100 times
faster than Wi-Fi, reaching speeds of 224 gigabits per
second.

16. It is wireless and uses visible light
communication or infra-red and near
ultraviolet (instead of radio frequency
waves) spectrum, parts of optical
wireless communications technology,
which carries much, more information,
and has been proposed as a solution
to the RF-bandwidth limitations. A
complete solution includes an industry
led standardization process

17. Li-Fi features include benefits to the
capacity, energy efficiency, safety and
security of a wireless system with a
number of key benefits over Wi-Fi but
are inherently a complementary
technology.
Features and Standards:

18. a) Capacity :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: Very high data rates can be achieved due to
low interference, high device bandwidths and high intensity
optical output.
 Planning: Capacity planning is simple since there tends to
be illumination infrastructure where people wish to
communicate, and good signal strength can literally be
seen.

19. b) Efficiency
 Low cost: 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.

20. c) Safetyc) Safety
 Safe: Life on earth has evolved through
exposure to visible light. 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 in certain environments
.

21. d)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.

22. Technology Detail:

23. Wi-Fi vs. Li-Fi:
A fundamental communications principle is
that the maximum data transfer possible
scales with the electromagnetic frequency
bandwidth available. The radio frequency
spectrum is heavily used and regulated, and
there just isn’t enough additional space to
satisfy the growth in demand. So Li-Fi has
the potential to replace radio and microwave
frequency Wi-Fi.

24. Light frequencies on the electromagnetic spectrum are
underused, while to either side is congested. Philip Ronan,
CC BY-SA

25. Comparison:

26. Applications of Li-Fi:
 RF Spectrum Relief: Excess capacity demands of cellular
networks can be off-loaded to Li-Fi networks where
available. This is especially effective on the downlink where
bottlenecks tend to occur.
 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.
 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.
 Hazardous Environments: Li-Fi provides a safe
alternative to electromagnetic interference from radio
frequency communications in environments such as mines
and petrochemical plants.

27. Applications of Li-Fi:
 Hospital & Healthcare: Li-Fi emits no electromagnetic
interference and so does not interfere with medical instruments,
nor is it interfered with by MRI scanners.
 Aviation: 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. In-flight entertainment (IFE)
systems can also be supported and integrated with passengers’
own mobile devices.
 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.
 Vehicles & Transportation: LED headlights and tail-lights are
being introduced. Street lamps, signage and traffic signals are
also moving to LED. This can be used for vehicle-to-vehicle and
vehicle-to-roadside communications. This can be applied for road
safety and traffic management.

28. Applications of Li-Fi:
 RF Avoidance: Some people claim they are hypersensitive
to radio frequencies and are looking for an alternative. Li-Fi
is a good solution to this problem.
 Location Based Services (LBS): Highly accurate
location-specific information services such as advertising
and navigation that enables the recipient to receive
appropriate, pertinent information in a timely manner and
location.
 Toys: Many toys incorporate LED lights and these can be
used to enable extremely low-cost communication between
interactive toys.

29. Current development:
 PureLiFi and Lucibel industrialized LiFi
luminaries:
Edinburgh, 25 November 2015 –
pureLiFi, the light communications technology
company that leads the market in development
and commercialization of LiFi (the high speed,
bidirectional, networked and mobile wireless
communications using light) andLucibel, the
French company that specializes in the design of
new-generation lighting solutions based on the
LED technology, are to co-develop and market
Europe’s first, fully industrialized LiFi luminaire.

30. Current development:
 Li-1st
• The Li-1st provides the first major opportunity
for customers to rapidly develop and test
VLC applications for cost-effective, high-speed
data communication solutions that utilize
commercial light Li-1st.
• The Li-1st has been created to provide a
platform for pilot projects with pure LiFi
partners, and to establish engagement on pure
LiFi’s high-speed technology path, upon which
this product is the initial step.
• The system will be available on limited release
from January 2014.

31.  Li-Flame:
• The Li-Flame is the next generation of the
world’s first ubiquitous high-speed wireless
network solution using VLC. Li-Flame
technology delivers data densities substantially
greater than state-of-the-art Wi-Fi solutions
and its inherent security properties eliminate
unwanted external network intrusion. In
addition, the merger of illumination with
wireless communications provides a
measurable reduction in both infrastructure
complexity and energy consumption
Current development:

32.  Li-Flame delivers:
• Half duplex communication with a 10Mbps downlink and
10Mbps uplink over a range of up to three meters with
standard light fixtures; this results in a data rate density
of 2Mbps per square meter
• Full mobility (portable, battery-powered desktop unit)
with high data rate due to dense installation of Li-Fi
access points (APs)
• Multiple users per Li-Fi AP, supported through multiple
access, while retaining high bandwidth for each user
• Secure wireless communications constrained by walls,
eliminating the risk of signal leakage to external
eavesdroppers
Current development:

33.  Li-Flame delivers:
• Safe wireless communication in environments where
radio frequencies are undesirable or unavailable
• More flexible construction environments with the
elimination of communication cabling
• An extensive range of wireless communication
applications including and beyond existing Wi-Fi
• A cost-effective delivery of light and data via a single
infrastructure
• Multiple APs throughout an indoor space form an auto-
cellular network, allowing users to move from one AP to
the next without any interruption in its high-speed data
stream
Current development:

34. Current development:
 Li-Flame Ceiling Unit (CU):
• Data and power via standard Ethernet
port
• Simple installation
• Connects to an LED light fixture to form
an auto-cell over a wide area
• Multiple accesses
• Handover control enables seamless
switching between APs

35. Current development:
 Li-Flame Desktop Unit (DU)
• Connects to client device via USB
• 10Mbps infrared uplink to ceiling unit
• Handover capable, allowing user to
move from one AP to the next without
losing the high-speed data connection
• Transceiver swivel head can be adjusted
by user to optimize the connection
• Battery-powered and portable