Wi-Fi


Wi-Fi
is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point (or hotspot) has a range of about 20 meters (65 ft) indoors and a greater range outdoors. Multiple overlapping access points can cover large areas.

“Wi-Fi” is a trademark of the Wi-Fi Alliance and the brand name for products using the IEEE 802.11 family of standards. Wi-Fi is used by over 700 million people. There are over four million hotspots (places with Wi-Fi Internet connectivity) around the world, and about 800 million new Wi-Fi devices are sold every year.[citation needed] Wi-Fi products that complete Wi-Fi Alliance interoperability certification testing successfully may use the “Wi-Fi CERTIFIED” designation and trademark.

Uses

To connect to a Wi-Fi LAN, a computer has to be equipped with a wireless network interface controller. The combination of computer and interface controller is called a station.
All stations share a single radio frequency communication channel.
Transmissions on this channel are received by all stations within range.
The hardware does not signal the user that the transmission was
delivered and is therefore called a best-effort delivery mechanism. A carrier wave is used to transmit the data in packets, referred to as “Ethernet frames“. Each station is constantly tuned in on the radio frequencycommunication channel to pick up available transmissions.

Internet access

A Wi-Fi-enabled device, such as a personal computer, video game console, smartphone or digital audio player, can connect to the Internet when within range of a wireless network connected to the Internet. The coverage of one or more (interconnected) access points—called
hotspots—comprises an area as small as a few rooms or as large as many
square miles. Coverage in the larger area may depend on a group of
access points with overlapping coverage. Wi-Fi technology has been used
successfully in wireless mesh networks in London, UK, for example.[1]

Wi-Fi provides service in private homes and offices as well as in
public spaces at Wi-Fi hotspots set up either free-of-charge or
commercially. Organizations and businesses,
such as airports, hotels, and restaurants, often provide free-use
hotspots to attract or assist clients. Enthusiasts or authorities who
wish to provide services or even to promote business in selected areas
sometimes provide free Wi-Fi access. As of 2008 more than 300 city-wide
Wi-Fi (Muni-Fi) projects had been created.[2] As of 2010 the Czech Republic had 1150 Wi-Fi based wireless Internet service providers.[3][4]

Routers that incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, often set up in homes and other buildings, provide Internet access and internetworking to all devices tuned into them, wirelessly or via cable. With the emergence of MiFi and WiBro (a portable Wi-Fi router) people can easily create their own Wi-Fi hotspots that connect to Internet via cellular networks. Now iPhone, Android, Bada and Symbian phones can create wireless connections.[5]

One can also connect Wi-Fi devices in ad-hoc mode
for client-to-client connections without a router. Wi-Fi also connects
places normally without network access, such as kitchens and garden
sheds.

Source: wikipedia.org