how does wifi work?

A wireless network uses radio waves, such as mobile phones,
televisions and radios. In fact, communication across a wireless network
is a bit like two-way radio communications. Here’s what happens:

1. A computer on the wireless adapter
translates data into a radio signal and transmits through an antenna.

2. A wireless router
receives the signal and decodes.
The router sends information to the Internet using a physical, wired
Ethernet connection.This process also works in reverse, with the router
receiving information from the Internet, translating it into a radio
signal and send it to your wireless adapter
. Radios
used for WiFi communication are very similar to those used for
walkie-talkie radios, cell phones and other devices. They can send and
receive radio waves, and they can convert 1s and 0s into radio waves and
convert the radio waves in 1 and 0 But WiFi radios have some notable
differences from other radios:

* They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is
much higher than the frequencies used for cellular phones,
walkie-talkies and televisions. Increase the frequency of the signal can
carry more data.

* They use 802.11 networking standards that are in several variants:

o 802.11a transmit at 5 GHz and up to 54 megabits of data per second
. He also uses orthogonal frequency-division multiplexing (OFDM), a more efficient coding
technique
that splits the radio signal into several sub-signals before they reach a receiver. This reduces interference.

o 802.11b is the slowest and least expensive standard. For a time, has
seen its costs, but it is now less common for a faster cheaper. 802.11b
transmit in the frequency band 2.4 GHz radio spectrum use. It can handle
up to 11 megabits of data per second, and using additional code
before (CCK) to improve the speed of modulation.

o 802.11g transmit at 2.4 GHz like 802.11b, but it is much faster – it
can handle up to 54 megabits of data per second. 802.11g is faster
because it uses the same OFDM coding as 802.11a.

o The new 802.11n standard, which is widely available. This standard
significantly improves speed and range. For instance, although 802.11g
theoretically moves 54 megabits of data per second, making real-world
speeds of around 24 megabits of data per second because of congestion in
the network. 802.11n, however, allegedly can reach speeds as high as
140 megabits per second. The standard is currently in draft – Institute
of Electrical and Electronics Engineers (IEEE) plans to formally ratify
802.11n by the end of 2009.

* Other 802.11 standards focus on applications
of wireless networks such as wide-area network (WAN) in vehicles or
technology that allows you to switch from one wireless network to
another without problems.

* WiFi radios can transmit on any of three frequency bands. Or they can
“frequency hop” rapidly between the different bands. Frequency hopping
reduces interference and allows multiple devices to use the same
wireless connection simultaneously.