Li-Fi is a known as Light Fidelity, which is based on visible light communication and optical communication.

2. Basic of the Li-Fi
 Li-Fi work on the base of the optical communication
 In the Li-Fi the data should be transmitted in the light form(visible light form)
 For the transmit data in the Li-Fi generally LED source use in the Li-Fi
 And as the part of receiver side the Photodiode or Photo resistor are used for
captureVisible Light.
 Li-Fi having more speed to transfer data from router to coordinator than the
Bluetooth and Wi-Fi communication.
 Li-Fi data rate was up to 100MBps and its up to 10gbps can be increase.
 Li-Fi is IEEE 802.15 standardize wireless communication system.

3. Comparison between Electromagnetic spectrum and
Visible Light spectrum

4. Network- Wi-Fi allocated network

5. Network- Li-Fi allocated attocell network

6. How Li-Fi Operate
LED Driver
Data in form of visible light
TX
Photo detector device
RX

7. Input Device
 As a input device any computer or input transducers are attached
 For example a simple audio player can be attached as input device
 And Computer can be used as input device if any data stream want to send
or any other form data if we want to transmit
 Now those days as Audio transmitting used using visible light
 And in some application videos are also transmitted
 Input device it‟s a input like keyboard used in PC for typing or as a input
peripheral

8. LED Driver
 Led driver was a LED input to output driver that control voltage and
amplitude of the given input.
 The LED driver is a one type of transducer that convert data in one form
to another.
 LED driver sends data in form of “1” and “0” .
 And LED Blink when “1” transmitted and LED was off when “0”
transmitted.
 LED driver control the incoming stream from the input device.

9. Visible Light
 The transmitted data in visible light form so it can use for both purpose for
as general purpose light as well as for data transmitting too.
 This visible light actually high speed diming of LED light, that so high speed
ON and OFF LEDs but that speed so high so human eye can not detect
that changes.
 That data in ON means „1‟ and OFF means „0‟ form but usually we see only
visible light not its data changes 1‟s and 0‟s.

10. Photo Detecting Device
 Generally as photo detecting device we used Photo Detector.
 That photo detector detect light intensity changes and its 1‟s and 0‟s
changes and convert that data in light form to electric form or in current
form .
 Here the photo detector work as aTransducer, that convert data in one
form to another.
 Photo detector detect slight changes in visible light that strikes on that in
ON and OFF mode changes, and that 1‟ and 0‟s converting in electrical
form and after than it amplifies using amplifier, and getting original massage
or data.

11. Output Device
 As output device any other device used that give us proper output or any
other transducers.
 If we normally send voice or any sound stream in visible light form than as
output side normally we used speaker.
 Output device is final source that give output signal, and it can be
destination part of signal.

12. Inventor of LI-Fi
Professor Harald Haas invent the first Li-Fi technology for visible light
communication.

13. Li-Fi Future expansions
 Smart Moll
 Advertising of Shops
 Smart Cities
 Smart Homes
 Internet of Things
 Future Cellular Communication
 Visible Spectrum/Light Communication
Etc….

14. Reference
 Professor Harald Haas documentaries- http://www.eng.ed.ac.uk/drupal/hxh
 Visible Light Communication Using OFDM- Mostafa Z.Afgani, Harald Haas, Hany Elgala,
and Dietmar Knipp School of Engineering and Science International University Bremen 28759
Bremen, Germany
 Optical Wireless OFDM System on FPGA: Study of LED Nonlinearity Effects Irina
Stefan∗, Hany Elgala∗, Raed Mesleh, Dominic O‟Brien and Harald Haas∗, Jacobs University
Bremen, Campus Ring 1, 28759 Bremen, Germany
 Self Organising Interference Coordination in Optical Wireless Networks- Birendra
Ghimire and Harald Haas School of Engineering and Science, Jacobs University Bremen, 28759,
Bremen, Germany Institute for Digital Communications, University of Edinburgh, EH9 3JL,
Edinburgh, UK
 Optical Wireless Transmitter Employing Discrete Power Level Stepping- Thilo Fath,
Christoph Heller, and Harald Haas, Member, IEEE
 High-speed wireless networking using visible light- Harald Haas
 Google
 Wikipedia