For IT Students and developers

1. WI-FI
ABBREVIATION:
WIFI stands for:
 Wireless Internet for Frequent Interface.
 Wireless Fidelity.
 Wire Free Internet.
DEFINITION:
Wi-Fi is the name of a wireless networking technology that
uses radio waves to provide high-speed network and Internet
connections.

2. WI-FI
Introduction to Wi-Fi Technology:
 Wi-Fi allows networking of computers and digital devices without the need for
wires.
 Data is transferred over radio frequencies, allowing Wi-Fi capable devices to
receive and transmit data when they are in range of a Wi-Fi network.

3. WI-FI
 . Wi-Fi uses a radio technology known as 802.11, which can transmit data over short distances
using high frequencies.
 The widespread use of the technology and its availability in both residential homes and public
places – including parks, gathering spots, and coffee shops – have made it one of the most
popular data transmission technologies available today.

4. WI-FI
WORKING OF WIFI:
 Like mobile phones, a Wi-Fi network makes use of radio waves to transmit
information across a network.
 The computer should include a wireless adapter that will translate data sent into a
radio signal.
 This same signal will be transmitted, via an antenna, to a decoder known as the
router.

5. WI-FI
WI-FI DEVICES:
 There are all kinds of cool tech devices that can take advantage of that connection
everything from Blue-ray players to digital photo frames to eBook readers.
Some Wifi devices such as wacky, some whimsical, and most are eminently practical.
The products in our Wi-Fi device roundup:
 Apple iPod
Toshiba UX600 Series HDTV
Samsung HMX-S15 32GB SSD Full HD Camcorder w/ Wi-Fi

6. WI-FI
 Erector Spykee Robot, Eye-Fi Geo X, Iomega I Connect
Wireless Data Station
 Logitech Squeezebox Radio, Monsoon Titanium HD Wi-Fi
 ThinkGeek Wi-Fi Detector Cap
 Visio VBR200W Blue-ray Player
 And the Witlings Body Scale.

7. Performance
 802.11a offers speeds with a theoretically maximum rate of
54Mbps in the 5 GHz band
 802.11b offers speeds with a theoretically maximum rate of
11Mbps at in the 2.4 GHz spectrum band
 802.11g is a new standard for data rates of up to a theoretical
maximum of 54 Mbps at 2.4 GHz.

8. What is 802.11?
 A family of wireless LAN (WLAN) specifications developed
by a working group at the Institute of Electrical and
Electronic Engineers (IEEE)
 Defines standard for WLANs using the following four
technologies
 Frequency Hopping Spread Spectrum (FHSS)
 Direct Sequence Spread Spectrum (DSSS)
 Infrared (IR)
 Orthogonal Frequency Division Multiplexing (OFDM)
 Versions: 802.11a, 802.11b, 802.11g, 802.11e, 802.11f,
802.11i

9. 802.11a
 Employs Orthogonal Frequency Division Multiplexing (OFDM)
 Offers higher bandwidth than that of 802.11b, DSSS (Direct
Sequence Spread Spectrum)
 802.11a MAC (Media Access Control) is same as 802.11b
 Operates in the 5 GHz range

10. 802.11a Advantages
 Ultra-high spectrum efficiency
 5 GHz band is 300 MHz (vs. 83.5 MHz @ 2.4 GHz)
 More data can travel over a smaller amount of bandwidth
 High speed
 Up to 54 Mbps
 Less interference
 Fewer products using the frequency
 2.4 GHz band shared by cordless phones, microwave ovens,
Bluetooth, and WLANs

11. 802.11a Disadvantages
 Standards and Interoperability
 Standard not accepted worldwide
 No interoperability certification available
for 802.11a products
 Not compatible or interoperable with 802.11b
 Legal issues
 License-free spectrum in 5 GHz band not
available worldwide
 Market
 Beyond LAN-LAN bridging, there is limited interest for
5 GHz adoption

12. 802.11a Vs. 802.11b
802.11a vs. 802.11b 802.11a 802.11b
Raw data rates Up to 54 Mbps
(54, 48, 36, 24,18, 12 and 6
Mbps)
Up to 11 Mbps
(11, 5.5, 2, and
1 Mbps)
Range 50 Meters 100 Meters
Bandwidth UNII and ISM
(5 GHz range)
ISM (2.4000—
2.4835 GHz range)
Modulation OFDM technology DSSS technology

13. 802.11g
 802.11g is a high-speed extension to 802.11b
 Compatible with 802.11b
 High speed up to 54 Mbps
 2.4 GHz (vs. 802.11a, 5 GHz)
 Using ODFM for backward compatibility
 Adaptive Rate Shifting

14. 802.11g Advantages
 Provides higher speeds and higher capacity requirements
for applications
 Wireless Public Access
 Compatible with existing 802.11b standard
 Leverages Worldwide spectrum availability
in 2.4 GHz
 Likely to be less costly than 5 GHz alternatives
 Provides easy migration for current users of 802.11b
WLANs
 Delivers backward support for existing 802.11b products
 Provides path to even higher speeds in the future

15. 802.11e Introduces Quality of Service
 Also know as P802.11 TGe
 Purpose:
 To enhance the 802.11 Medium Access
Control (MAC) to improve and manage
Quality of Service (QoS)
 Cannot be supported in current chip design
 Requires new radio chips
 Can do basic QoS in MAC layer

16. 802.11f – Inter Access Point Protocol
 Also know as P802.11 TGf
 Purpose:
 To develop a set of requirements for Inter-Access Point Protocol
(IAPP), including operational and management aspects

17. “Li-Fi”

18. LI-FI
ABBREVIATION:
LIFI stands for:
 Life Impact Foundation International.
 Latino International Film Institute.
 Laser Induced Fluorescence Imaging.
DEFINITION:
Li-Fi is a wireless optical networking technology that uses light-emitting diodes (LEDs)
for data transmission. It is the fast and cheap wireless communication system which is
optical version of Wi-Fi.

19. LI-FI
INTRODUCTION TO LI-FI TECHNOLOGY:
 Li-Fi (Light Fidelity) is a bidirectional, high speed and fully networked wireless
communication technology similar to Wi-Fi.
 The term was coined by Harald Haas .
 It is a form of visible light communication and a subset of optical wireless
communications (OWC) and could be a complement to RF communication (Wi-
Fi or Cellular network), or even a replacement in contexts of data broadcasting.

20. LI-FI
 It is so far measured to be about 100 times faster than some Wi-
Fi implementations, reaching speeds of 224 gigabits per second.
 It is wireless and uses visible light communication or infra-red and near
ultraviolet (instead of radio frequency waves) spectrum, part of optical
wireless communications technology, which carries much more information,
and has been proposed as a solution to the RF-bandwidth limitations.

21. LI-FI
WORKING OF LI-FI:
 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.
2) A light source equipped with a signal processing unit.
 A VLC light source could comprise of a fluorescent or light emitting diode (LED)
bulb.

22. DEVICES OF LI-FI
DEVICES OF LI-FI:
 Be among the first in the world to test this new technology LIFI or Light
Fidelity with our GEO LIFI XS KIT.
 The technology LIFI is a new wireless communication technology using the
light issued from our LIFI READY Led lamps.
 LIFI has the advantage of being useful in electromagnetic sensitive areas
such as in aircraft cabins, hospitals and nuclear power plants

23. DEVICES OF LI-FI
 Be among the first in the world to test this new technology LIFI or Light Fidelity
with our GEO LIFI WW12 ROUND KIT.
 The technology LIFI is a new wireless communication technology using the light
issued from our LIFI-READY Led lamps.
 LIFI has the advantage of being useful in electromagnetic sensitive areas such as
in aircraft cabins, hospitals and nuclear power plants.

24. WI-FI AND LI-FI
BEST:
Li-Fi is not the replacement of wifi technology. It can be considered as
incredible companion of the Wi-Fi technology. It operates between 380 nm to
780 nm optical range. Li-Fi is used to exchange data incredibly rapidly and
securely at much lower power level compare to Wi-Fi.