IEEE 802.11Definition :IEEE 802.11 is the setof standards that define communication for wireless LANs or WLANs.
Thetechnology used in 802.11 is branded to consumers as Wi-Fi.According to the name ,IEEE 802.
11 is overseen by the IEEE, specifically the IEEE LAN/MAN StandardsCommittee (IEEE 802). The current version now in use is of 802.11-2007. Actually, IEEE 802.11 is theset of technical steps for implementing Wi-Fi. Selling products under thistrademark is checked by an industry trade association named as Wi-Fi Alliance.
IEEE 802.11 standardshave its roots from a year 1985 decision by the U.S.
Federal Commission forCommunication that opened up the ISM band which has no license use. It wasformally released in 1997. That original standard was called IEEE 802.11-1997. “802.11 standards” or the “802.
11 family ofstandards” are commonly used. However to be more precise ,now this time onlyone standard existing is (IEEE 802.11-2007) but many changes commonly known as amendmentsinclude 802.11a ,802.11b, 802.11g, and 802.11n. This Linksys WRT54GS Wi-Fi router from 2005works on the 2.
4 GHz “G” standard, is able to transmit 54 megabitsper second. TheNetgear dual-band router from 2013 uses the AC standard, is able totransmit 1900 megabits per second. Brief Description:The 802.11 family consistsof a series of half-duplex over-the-air modulation techniquesthat use the same basic protocol. The first wireless networking standard in thefamily was 802.11-1997 , but on market 802.11b was the first time widelyaccepted, supported by 802.11a, 802.
11g, 802.11n, and 802.11ac. Other standards(c–f, h, j) are service changes that are used to extend the idea of the existingstandard.802.
11b and 802.11g bothuse the 2.4 GHz ISM band ,nowit is operating in the United States under Part15 ofthe U.S.
Federal Communications Commission Rulesand Regulations. By using this choice offrequency band, 802.11b and g equipment and this suffering occasionally interference of microwave ovens, cordlesstelephones,and Bluetooth devices.802.
11b and 802.11g able to control their interference and interference byusing direct-sequence spread spectrum and OFDM signaling methods. 802.11a uses the 5 GHz U-NII band, For larger part of theworld, offers at least 23 not able to interact with channels rather than the2.
4 GHz ISM frequency band offering only three not able to interactchannels, where other adjacent channels interact —see listof WLAN channels. Better or worse performance with higher orlower frequencies (channels) may be realized, depending on the environment.802.11n can use either the 2.4 GHz or the 5 GHz band; 802.11ac usesonly the 5 GHz band.The segment of the radio frequency spectrumused by 802.
11 varies between countries. In the US, 802.11a and 802.11g devicesmay be operated without a license, as allowed in Part 15 of the FCC Rules andRegulations. Frequencies used by channels one through six of 802.11b and802.
11g fall within the 2.4 GHz amateur radio band.Licensed amateur radio operators may operate 802.11b/g devices under Part97 ofthe FCC Rules and Regulations, allowing increased power output but notcommercial content or encryption. Wireless Standards802.11a, 802.11b/g/n:802.
11a is the first Wi-Fiwireless network communication standards which iscreated in the IEEE 802.11 standards family.Historyof 802.11a:The 802.11a specification was ratified in 1999. At thattime, the only other Wi-Fi technology being readied for the marketwere 802.11b.
(Theoriginal 802.11 didnot gain widespread deployment due to its excessively slow speed.) 802.
11a andthese other standards were incompatible, meaning that 802.11a devices cannotcommunicate with the other kinds and vice versa.An 802.11a wireless network supports a maximumtheoretical bandwidth of 54 Mbps,substantially better than the 11 Mbps of 802.11b and on par with what 802.11gwould startto offer a few years later.
The performance of 802.11a made it an attractivetechnology, but achieving that level of performance required using relativelyhigher cost hardware.802.11a gained some adoption in corporate networkenvironments where cost was less of an issue. Meanwhile, 802.11b and early homenetworking exploded in popularity during the same time period. 802.11b and then802.
11g (802.11b/g) networks dominated the industry within a few years. Somemanufacturers built devices with both A and G radios integrated so that theycould support either standard on so-called a/b/g networks, although these wereless common as relatively few A client devices existed.Eventually, 802.11aphased out of the market in favor of newer standards.
802.11a should not beconfused with 802.11ac, a muchnewer and more advanced standard.802.11aand Wireless Signaling:U.S. government regulators in the 1980s opened threespecific wireless frequency bands for public use – 900 MHz (0.
9GHz), 2.4 GHz, and 5.8 GHz (sometimes called 5 GHz).
900 MHz proved too low offrequency to be useful for data networking, although cordless phones usedit widely.802.11a transmits wireless spread spectrum radio signals in the 5.8 GHz frequency range. Thisband was regulated in the U.S.
and many countries for a long time, meaningthat 802.11a networks did not have to contend with signal interference fromother kinds of transmitting devices. 802.11b networks utilized frequenciesin the often unregulated 2.4 GHz range and were much more susceptible to radiointerference from other devices.802.
11b was the first Wi-Fi wireless networkcommunication technology to gain mass adoption with consumers. It is one ofmany Institute of Electrical and Electronics Engineers(IEEE) standards in the 802.11 family. 802.11b products were made obsolete andphased out by the newer 802.11g and 802.
11n Wi-Fi standards.History of 802.11bUntil the mid 1980s, the use of radio frequency space around2.
4 GHz was regulated by government agencies around theworld.The U.S. Federal Communications Communication (FCC) initiatedthe change to deregulate this band, previously limited to so-called ISM(industrial, scientific, and medical) equipment. Their goal was to encouragethe development of commercial applications.Building commercial wireless systems on a large scale requiressome level of technical standardization among vendors.
That’s where the IEEEstepped in and assigned its 802.11 working group to design a solution, whicheventually became known as Wi-Fi. The first 802.11 Wi-Fi standard,published in 1997, had too many technical limitations to be widely useful, butit paved the way for the development of a second generation standard called802.11b.
802.11b (nowadays called “B” for short) helpedlaunch the first wave of wireless home networking. With its introduction in1999, manufacturers of broadband routers like Linksys began selling Wi-Fi routersalongside the wired Ethernet models they had been producing before.
Though these older products could be difficult to set up andmanage, the convenience and potential demonstrated by 802.11b turned Wi-Fiinto a huge commercial success.802.11b Performance:802.11b connections support a theoretical maximum data rateof 11 Mbps.
Although comparable to traditional Ethernet (10 Mbps), B performs significantlyslower than all newer Wi-Fi and Ethernet technologies.802.11b and WirelessInterference:Transmitting in the unregulated 2.4 GHz frequency range, 802.
11btransmitters can encounter radio interference from other wireless householdproducts like cordless telephones, microwave ovens, garage door openers, andbaby monitors.802.11 and BackwardCompatibility:Even the newest Wi-Fi networks still support 802.11b. That’sbecause each newer generation of the main Wi-Fi protocol standards hasmaintained backward compatibility with all previous generations: For example, 802.11g routers and access points support both G and B clients – called 802.11b/g networks 802.
11n routers and access points support N, G and B clients – 802.11b/g/nnetworks 802.11ac routers and access points support AC, N, G and B clients – 802.
11b/g/n/ac networksThis backward compatibility feature has proven critical to thesuccess of Wi-Fi, as consumers and businesses can add newer equipment to theirnetworks and gradually phase out old devices with mimimal disruption.802.11g is an IEEE standard Wi-Fi wireless networking technology.
Like other versionsof Wi-Fi, 802.11g (sometimes referred to simply as “G”)supports wireless local area network (WLAN) communicationsamong computers, broadband routers, and many other consumer devices. G was ratified in June of 2003, and replaced the older 802.11b (“B”) standard, latereventually replaced by 802.
11n (“N”) and newer standards.How Fast Is 802.11g:802.11g Wi-Fi has ability to support a maximum network bandwidth of 54 Mbps, which is higher than the 11 Mbps rating of B and less than the 150 Mbps or greater speeds ofN. Similarly many other kindsof networking, G is not able to achieve the maximum rating in practice; 802.
11gconnections hit an application datatransfer rate limit between 24 Mbps and 31 Mbps. Working: G incorporated is a radio communication technique known as OrthogonalFrequency Division Multiplex that was introduced to Wi-Fi with 802.11a . OFDM technology enabled G and A to get greater network performance than B.On the other hand, 802.
11g chosen the same 2.4 GHz range of communicationfrequencies introduced to Wi-Fi with802.11b.Using this frequency gave Wi-Fi devices greater signal range than what A can offer.
14possible channels that 802.11g can work on, though some are illegal in somecountries. The frequencies from channel 1-14 range between 2.412 GHz to 2.484GHz.
G was specially designed for cross compatibility.What is meanings of thatdevices can coordinate wireless networks even when the wireless access point runs a different Wi-Fi version.The newest 802.
11ac Wi-Fi equipment today can supportconnections from G clients.802.11g for HomeNetworking and Travel:Numerous brands and models of computer laptops and other Wi-Fidevices were manufactured with Wi-Fi radios supporting G. As it combined someof the best elements of A and B, 802.
11g became the predominant Wi-Fi standardat a time when the adoption of home networking exploded worldwide.Many homenetworks today still operate using 802.11g routers. At 54 Mbps, these routers can keep up withmost high-speed home internet connections including basic video streaming andonline gaming usages.They can be found inexpensively through both retail andsecondhand sales outlets. However, G networks can reach performance limitsquickly when multiple devices are connected and simultaneously active, but thisis true for any network that’s consumed by too many devices.
In addition to Grouters designed for fixed installation in homes, 802.11g travel routers also gained substantial popularity withbusiness professionals and families who needed to share a single wired Ethernet connection among their wirelessdevices.G (and some N) travel routers can still be found in retail outlets buthave become increasingly uncommon as hotel and other public internet servicesshift from Ethernet to wireless hotspots.
802.11n is a standard (IEEE) for Wi-Fi wireless local network communications, contract in2009.802.11n is designed to exchange the 802.11a, 802.11b and 802.11g Wi-Fitechnologies. Wireless Technologies in 802.
11n:802.11n uses multiple wirelessantennas in tandem for transmitting and receiving data. The term MIMO refers tothe ability of 802.11n and like other technologies to coordinate multiplesimultaneous radio signals. MIMO is used to increase the range and throughput of a wirelessnetwork.
An other technique employed by 802.11n that involves increasing thechannel bandwidth. Such networks802.11a/b/g, and each .11n device that uses a preset Wi-Fi channel on which isused for transmitting. Such channel will use a larger frequency range , alsoincreasing data throughput.802.
11nPerformance:802.11nconnections that support maximum theory based network bandwidth upto300 Mbpswhich primarily depends on the number ofwireless radios incorporated into devices.