WiFi has a lot of advantages. wireless networks are easy to set up and inexpensive. wireless networks use radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication. here's what happens:
- a computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
- a wireless router receives the signal and decodes it. It sends the information to the internet using a physical, wired ethernet connection.
the process also works in reverse, with the router receiving information from the Internet, translating it into a radio signal and sending it to the computer's wireless adapter. the radios used for WiFi communication are very similar to the radios used for walkie-talkies, cell phones and other devices. they can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and convert the radio waves back into 1s and 0s. but WiFi radios have a few notable differences from other radios:
transmission frequencies
they transmit at frequencies of 2.4 GHz or 5GHz. This frequency is considerably higher than the frequencies used for cell phones, walkie-talkies and televisions. The higher frequency allows the signal to carry more data. WiFi radios can transmit on any of three frequency bands. Or, they can "frequency hop" rapidly between the different bands. Frequency hopping helps reduce interference and lets multiple devices use the same wireless connection simultaneously.
WiFi standards
- 802.11a transmits at 5GHz and can move up to 54 megabits of data per second. It also and uses OFDM coding.
- 802.11b was the first version to reach the marketplace. It's the slowest and least expensive standard, and it's becoming less common as faster standards become less expensive. 802.11b transmits in the 2.4 GHz frequency band of the radio spectrum.
iIt can handle up to 11 megabits of data per second, and it uses complimentary code keying (CCK) coding.
- 802.11g also transmits at 2.4 GHz, but it's a lot faster than 802.11b.
it can handle up to 54 megabits of data per second. 802.11g is faster because it uses orthogonal frequency-division multiplexing (OFDM), a more efficient coding technique
. - 802.11n the latest line in the ever changing standard. transmits at both 2.4 GHz and 5GHz.
it can handle up to 248 megabits of data per second. only just coming onto the market place as this document was being created (2008)
