WiFi Technology

The Wi-Fi logo used by theWi-Fi Alliance.
Wi-Fi, also spelledWifiorWiFi, is alocal area wireless technologythat allows an electronic device to exchange data or connect to the internet using 2.4 GHzUHFand 5 GHzSHFISM radio bands.
The nameis a trademark, and is a play on theaudiophiletermHi-Fi. TheWi-Fi Alliancedefines Wi-Fi as any "wireless local area network" (WLAN) products that are based on theInstitute of Electrical and Electronics Engineers' (IEEE)802.11 standards".[1]However, since most modern WLANs are based on these standards, the term "Wi-Fi" is used in general English as a synonym for "WLAN". Only Wi-Fi products that complete Wi-Fi Allianceinteroperabilitycertification testing successfully may use the "Wi-Fi CERTIFIED" trademarkMany devices can use Wi-Fi, e.g., personal computers, video-game consoles,smartphones, digital cameras,tablet computersand digital audioplayers. These can connect to a network resource such as the Internet via awireless network access point. Such an access point(orhotspot) has a range of about 20 meters (66 feet) indoors and a greater range outdoors. Hotspot coveragecan comprise an area as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.Depiction of a device sending information wirelessly to another device, both connected to the local network, in order to print a document.Wi-Fi can be less secure than wired connections (such asEthernet) because an intruder does not need a physical connection. Web pages that useSSLare secure but unencrypted internet access can easily be detected by intruders. Because of this, Wi-Fi has adopted various encryption technologies. The early encryptionWEPproved easyto break. Higher quality protocols (WPA, WPA2) were added later. An optional feature added in 2007, calledWi-Fi Protected Setup(WPS), had a serious flaw that allowed an attacker to recover the router's password.[2]The Wi-Fi Alliance has since updated its test plan and certification program to ensure all newly certified devices resist attacks.HistoryMain article:Frequency-hopping spread spectrumOn August 11, 1942,U.S. Patent 2,292,387was granted to Hedy Kiesler Markey, Lamarr's married name at the time, and George Antheil. This early version of frequency hopping, although novel, soon was met with opposition from the U.S. Navy and was not adopted.[3]The idea was not implemented in the U.S. until 1962, when it was used by U.S. military ships during ablockade of Cubaafter the patent had expired. Lamarr's work was honored in 1997, when theElectronic Frontier Foundationgave her a belated award for her contributions. In 1998, anOttawawireless technology developer,Wi-LAN Inc., acquired a 49% claim to the patent from Lamarr for an undisclosed amount of stock.[4]Lamarr's and Antheil's frequency-hopping idea served as a basis for modernspread-spectrum communication technology, such asBluetooth,COFDM(used in Wi-Fi network connections), andCDMA(used in some cordless and wireless telephones).[5]Main article:History of IEEE 802.11In 1971,ALOHAnetconnected the Hawaii islands with a UHF wireless packet network. The protocol was an early forerunner toEthernet, and later the WiFi protocol.A 1985 ruling by the US Federal Communications Commission released theISM bandfor unlicensed use.[6]These frequency bands are the same onesused by equipment such as microwave ovens and are subject to interference.In 1991,NCR CorporationwithAT&T Corporationinvented the precursor to 802.11 intended for use in cashier systems. The first wireless products were under the nameWaveLAN.The Australian radio-astronomerJohn O'Sullivandeveloped a key patent used in Wi-Fi as a by-product in aCSIROresearch project, "a failed experiment to detect exploding mini black holes the size of an atomic particle".[7]In 1992 and 1996,Australianorganization CSIRO (the AustralianCommonwealth Scientific and Industrial Research Organisation) obtained patents[8]for a method later used in Wi-Fi to "unsmear" the signal.[9]Thefirst version of the 802.11 protocolwas released in 1997, and provided up to 2Mbit/s link speeds. This was updated in 1999 with802.11bto permit 11Mbit/s link speeds, and this proved to be popular.In 1999, theWi-Fi Allianceformed as a trade association to hold the Wi-Fi trademark under which most products are sold.[10]WiFI uses a large number of patents held by many different organizations.[11]In April 2009, 14 technology companies agreed to pay CSIRO $250 million for infringements on CSIRO patents.[12]Thisled to Australians labelling Wi-Fi as an Australian invention,[13]though this has been the subject of some controversy.[14][15]CSIRO won a further $220 million settlement for Wi-Fi patent-infringements in 2012 with global firms in the United States required to pay the CSIRO licensing rights estimated to be worth an additional$1 billion in royalties.[12][16][17]The nameThe termWi-Fi, commercially used at leastas early as August 1999,[18]was coined by a brand-consulting firm calledInterbrandCorporation. The Wi-Fi Alliance had hired Interbrand to determine a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'".[19][20][21]Phil Belanger, a founding member of the Wi-Fi Alliance who presided over the selection of the name "Wi-Fi", also stated that Interbrand inventedWi-Fias aplay on wordswithHi-Fi, and also created the Wi-Fi logo.The Wi-Fi Alliance used the "nonsense"advertising slogan"The Standard for Wireless Fidelity" for a short time after the brand name was invented, leading to the misconception that Wi-Fi was an abbreviation of "Wireless Fidelity"[19][22][23]Theyin-yangWi-Fi logo indicates the certification of a product forinteroperability.[22]Non-Wi-Fi technologies intended for fixed points such asMotorola Canopyare usually described asfixed wireless. Alternative wireless technologies include mobile phone standards such as2G,3G,4GorLTE.Wi-Fi certificationSee also:Wi-Fi AllianceTheIEEEdoes not test equipment for compliance with their standards. Thenon-profitWi-Fi Alliance was formed in 1999 to fill this void — to establish and enforce standards for interoperability andbackward compatibility, and to promotewirelesslocal-area-network technology. As of 2010, the Wi-Fi Alliance consisted ofmore than 375 companies from around theworld.[24][25]The Wi-Fi Alliance enforces the use of the Wi-Fi brand to technologies based on theIEEE 802.11standards from the IEEE. This includeswireless local area network(WLAN) connections, device to device connectivity(such as Wi-Fi Peer to Peer aka Wi-Fi Direct),Personal area network(PAN),local area network(LAN) and even some limitedwide area network(WAN) connections. Manufacturers with membership in the Wi-Fi Alliance, whose products pass the certification process, gain the right to markthose products with the Wi-Fi logo.Specifically, the certification process requires conformance to the IEEE