Wi-Fi allows devices to connect to the Internet and form local area networks wirelessly. The term Wi-Fi was coined in 1999 and resembles older "hi-fi" audio terms. Devices within range of a wireless network can connect to the Internet through an access point. Early plans for city-wide Wi-Fi networks proved difficult to implement at a large scale. Wi-Fi reduces network deployment and expansion costs compared to wired networks and operates in many public and private locations. Encryption has improved security but wireless networks still have limited range compared to wired networks. Common hardware for Wi-Fi includes routers, access points, and wireless adapters.

1. Wi-Fi
Technology
BY DILIP BHARDWAJ

2. Wi-Fi ?
The term Wi-Fi suggests Wireless Fidelity, resembling
the long-established audio-equipment classification
term high fidelity (in use since the 1930s) or Hi-Fi (used
since 1950)
The term Wi-Fi, first used commercially in August 1999,was
coined by a brand-consulting firm called Interbrand Corporation
that the Alliance had hired to determine a name that was "a
little catchier than Direct Sequence'".

3. Access Point
A roof-mounted Wi-Fi antenna
A Wi-Fi enabled device such as a personal computer, video
game console, smart phone or digital audio player can
connect to the Internet when within range of a wireless
network connected to the Internet.
An outdoor Wi-Fi access point
In the early 2000s, many cities around the world
announced plans for city-wide Wi-Fi networks. This
proved to be much more difficult than their promoters
initially envisioned with the result that most of these
projects were either canceled or placed on indefinite hold

4. Advantages
Wi-Fi allows the deployment of local area
networks (LANs) without wires for client
devices, typically reducing the costs of A keychain-size Wi-Fi
network deployment and expansion. detector
Wi-Fi operates in more than 220,000 public hotspots and in tens
of millions of homes and corporate and university campuses
worldwide. The current version of Wi-Fi Protected Access
encryption (WPA2) as of 2010 is considered secure, provided users
employ a strong passphrase.

5. A computer on the wireless
adapter translates data into a
radio signal and transmits
through an antenna.
A wireless router receives the
signal and decodes. The router
sends information to the
Internet using a physical, wired
Ethernet connection

6. Limitations
Wi-Fi networks have limited range. A typical wireless router using 802.11b or
802.11g with a stock antenna might have a range of 32 m (120 ft) indoors and
95 m (300 ft) outdoors.
The most common wireless encryption-standard, Wired Equivalent Privacy
(WEP), has been shown to be easily breakable even when correctly configured.
Wi-Fi Protected Access (WPA and WPA2) encryption, which became available in
devices in 2003, aimed to solve this problem.

7. Hardware
An embedded Router Board 112 with U.FL-RSMA pigtail
and R52 mini PCI Wi-Fi card widely used by wireless
Internet service providers
USB wireless
adapter
OSBRiDGE 3GN - 802.11n Access Point
and UMTS/GSM Gateway in one device

8. Home Networking
If you have multiple computers networked in your home, you can
create a wireless network with a wireless access point. If you have
multiple computers that are not networked, or if you want to
replace your Ethernet network, you need a wireless router. It is a
single unit that contains:
1. A port to connect to your cable modem
2. A router
3. An Ethernet hub
4. A firewall
5. A wireless access point