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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.
WI-FIIntroduction 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.
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.
WI-FIWORKING 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.
WI-FIWI-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 iPodToshiba UX600 Series HDTVSamsung HMX-S15 32GB SSD Full HD Camcorder w/ Wi-Fi
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.
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.
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
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
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
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
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
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
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
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
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
“Li-Fi”
LI-FIABBREVIATION: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.
LI-FIINTRODUCTION 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.
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.
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.
DEVICES OF LI-FIDEVICES 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
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.
WI-FI AND LI-FIBEST:
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.