In 1999 a new technology called Airport was introduced by Apple
Computers. The technology enabled a mobile user to establish and maintain a
connection to a network without being physically linked to it by some sort of
cable. This technology was then adopted and developed by the rest of the IT
industry, then changed to the name we are all familiar today, Wi-Fi stands for
wireless fidelity’. The use of wireless
technology is quickly becoming the most popular way to connect to a network.
Wi-Fi is one of the many available technologies that offer us the convenience
of mobile computing. The thought of working anywhere and sending data to and
from a device without physical connection is becoming increasingly attractive
for many consumers and businesses. The name of a popular wireless networking
technology that uses radio waves to provide wireless high-speed internet and
network connections. The Wi-Fi Alliance, the organization that owns the Wi-Fi
(registered trademark) term specifically defines Wi-Fi as any "wireless
local area network (WLAN) products that are based on the Institute of
Electrical and Electronics Engineers' (IEEE) 802.11 standards." Wi-Fi
works with no physical wired connection between sender and receiver by using
radio frequency (RF) technology, a frequency within the electromagnetic
spectrum associated with radio wave propagation.
Benefits of using Wi-Fi
Wi-Fi has a lot of advantages. Wireless networks are easy to set up and inexpensive. They're also unobtrusive -- unless you're on the lookout for a place to use your laptop, you may not even notice when you're in a hotspot. A wireless network uses 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:
1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
2. A wireless router receives the signal and decodes it. The router 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 Wi-Fi 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 Wi-Fi radios have a few notable differences from other radios: They transmit at frequencies of 2.4 GHz or 5 GHz. 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.
They use 802.11 networking standards, which come in several flavours:
802.11a transmits at 5 GHz and can move up to 54 megabits of data per second. It also uses orthogonal frequency-division multiplexing (OFDM), a more efficient coding technique that splits that radio signals into several sub-signals before they reach a receiver. This greatly reduces interference.
802.11b is the slowest and least expensive standard. For a while, its cost made it popular, but now 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. It can handle up to 11 megabits of data per second, and it uses complementary code keying (CCK) modulation to improve speeds.
802.11g transmits at 2.4 GHz like 802.11b, but it's a lot 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.
In : mobile