What Is WiFi?

<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJdggRQhIZcraXxoomGEsmkI-h6dJ7Cois5U1rGgHquVD5rZjPWiGjljA2MSG7Slg5X2VBomnqGhjt4vxJjgXt0P1Pc5ojrRn0kU3WQM7iaKz34OP8mXKgY3_77R_M3U8sKOTD6IHrxh8/s1600/images+(2).jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJdggRQhIZcraXxoomGEsmkI-h6dJ7Cois5U1rGgHquVD5rZjPWiGjljA2MSG7Slg5X2VBomnqGhjt4vxJjgXt0P1Pc5ojrRn0kU3WQM7iaKz34OP8mXKgY3_77R_M3U8sKOTD6IHrxh8/s1600/images+(2).jpg" /></a></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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:</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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:</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">They use 802.11 networking standards, which come in several flavors:</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">802.11a transmits at 5 GHz and can move up to 54 megabits of data per second. It also usesorthogonal frequency-division multiplexing (OFDM), a more efficient coding technique that splits that radio signal into several sub-signals before they reach a receiver. This greatly reduces interference.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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 usescomplementary code keying (CCK) modulation to improve speeds.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">802.11n is the most widely available of the standards and is backward compatible with a, b and g. It significantly improved speed and range over its predecessors. For instance, although 802.11g theoretically moves 54 megabits of data per second, it only achieves real-world speeds of about 24 megabits of data per second because of network congestion. 802.11n, however, reportedly can achieve speeds as high as 140 megabits per second. 802.11n can transmit up to four streams of data, each at a maximum of 150 megabits per second, but most routers only allow for two or three streams.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">802.11ac is the newest standard as of early 2013. It has yet to be widely adopted, and is still in draft form at the Institute of Electrical and Electronics Engineers (IEEE), but devices that support it are already on the market. 802.11ac is backward compatible with 802.11n (and therefore the others, too), with n on the 2.4 GHz band and ac on the 5 GHz band. It is less prone to interference and far faster than its predecessors, pushing a maximum of 450 megabits per second on a single stream, although real-world speeds may be lower. Like 802.11n, it allows for transmission on multiple spatial streams -- up to eight, optionally. It is sometimes called 5G WiFi because of its frequency band, sometimes Gigabit WiFi because of its potential to exceed a gigabit per second on multiple streams and sometimes Very High Throughput (VHT) for the same reason.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">Other 802.11 standards focus on specific applications of wireless networks, like wide area networks (WANs) inside vehicles or technology that lets you move from one wireless network to another seamlessly.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">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.</span></span></div><div style="background-color: white; margin-top: 15px; padding: 0px;"><span style="font-family: arial, helvetica, clean, sans-serif;"><span style="line-height: 20px;">As long as they all have wireless adapters, several devices can use one router to connect to the Internet. This connection is convenient, virtually invisible and fairly reliable; however, if the router fails or if too many people try to use high-bandwidth applications at the same time, users can experience interference or lose their connections. Although newer, faster standards like 802.11ac could help with that.</span></span></div></div>

What Is WiFi?

A wireless network uses radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a...

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