Wi-Fi is technology for radio wireless local area networking of devices based on the IEEE 802.11 standards. Wi‑Fi is a trademark of the Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing.
Introduced = September 1998; 20 years ago
Compatible hardware = Personal computers, gaming consoles, televisions, printers, mobile phones.
Devices that can use Wi-Fi technologies include desktops and laptops, video game consoles, smartphones and tablets, smart TVs, digital audio players and modern printers. Wi-Fi compatible devices can connect to the Internet via a WLAN and a wireless access point. Such an access point (or hotspot) has a range of about 20 meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can be 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. Wi-Fi most commonly uses the 2.4 gigahertz (12 cm) UHF and 5.8 gigahertz (5 cm) SHF ISM radio bands, these bands are subdivided into multiple channels. Each channel can be time-shared by multiple networks. These wavelengths work best for line-of-sight. Many common materials absorb or reflect them, which further restricts range, but can tend to help minimise interference between different networks in crowded environments. At close range, some versions of Wi-Fi, running on suitable hardware can achieve speeds of over 1 Gbps.
Anyone within range with a wireless network interface controller can attempt to access a network; because of this, Wi-Fi is more vulnerable to attack (called eavesdropping) than wired networks. Wi-Fi Protected Access is a family of technologies created to protect information moving across Wi-Fi networks and includes solutions for personal and enterprise networks. Security features of Wi-Fi Protected Access have included stronger protections and new security practices as the security landscape has changed over time.
In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet network. ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, and later the IEEE 802.11 protocols, respectively. A 1985 ruling by the U.S. Federal Communications Commission released the ISM band for unlicensed use.These frequency bands are the same ones used by equipment such as microwave ovens and are subject to interference. In 1991, NCR Corporation with AT&T Corporation invented the precursor to 802.11, intended for use in cashier systems, under the name WaveLAN.
The Australian radio-astronomer Dr John O'Sullivanwith his colleagues Terence Percival, Graham Daniels, Diet Ostry, and John Deane developed a key patent used in Wi-Fi as a by-product of a Commonwealth Scientific and Industrial Research Organisation(CSIRO) research project, "a failed experiment to detect exploding mini black holes the size of an atomic particle". Dr O'Sullivan and his colleagues are credited with inventing Wi-Fi. In 1992 and 1996, CSIRO obtained patents for a method later used in Wi-Fi to "unsmear" the signal. The first version of the 802.11 protocol was released in 1997, and provided up to 2 Mbit/s link speeds. This was updated in 1999 with 802.11b to permit 11 Mbit/s link speeds, and this proved to be popular. In 1999, the Wi-Fi Alliance formed as a trade association to hold the Wi-Fi trademark under which most products are sold.
Wi-Fi uses a large number of patents held by many different organizations. In April 2009, 14 technology companies agreed to pay CSIRO $1 billion for infringements on CSIRO patents. This led to Australia labeling Wi-Fi as an Australian invention, though this has been the subject of some controversy.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.In 2016, the wireless local area network Test Bed was chosen as Australia's contribution to the exhibition A History of the World in 100 Objects held in the National Museum of Australia.
The name Wi-Fi, commercially used at least as early as August 1999, was coined by the brand-consulting firm Interbrand. The Wi-Fi Alliance had hired Interbrand to create a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'."Phil Belanger, a founding member of the Wi-Fi Alliance who presided over the selection of the name "Wi-Fi", has stated that Interbrand invented Wi-Fi as a pun upon the word hi-fi. Interbrand also created the Wi-Fi logo. The yin-yangWi-Fi logo indicates the certification of a product for interoperability.
The Wi-Fi Alliance used the nonsense advertising slogan "The Standard for Wireless Fidelity" for a short time after the brand name was created. The name was, however, never officially "Wireless Fidelity".Nevertheless, the Wi-Fi Alliance was also called the "Wireless Fidelity Alliance Inc" in some publications and the IEEE's own website has stated "WiFi is a short name for Wireless Fidelity". Non-Wi-Fi technologies intended for fixed points, such as Motorola Canopy, are usually described as fixed wireless. Alternative wireless technologies include mobile phone standards, such as 2G, 3G, 4G, and LTE. The name is sometimes written as WiFi, Wifi, or wifi, but these are not approved by the Wi-Fi Alliance.
Wi-Fi Ad-Hoc Mode:
Wi-Fi nodes operating in ad-hoc mode refers to devices talking directly to each other without the need to first talk to an access point (also known as base station). Ad-hoc mode was first invented and realized by Chai Keong Toh in his 1996 invention of Wi-Fi ad-hoc routing, implemented on Lucent WaveLAN 802.11a wireless on IBM ThinkPads over a size nodes scenario spanning a region of over a mile. The success was recorded in Mobile Computingmagazine (1999) and later published formally in IEEE Transactions on Wireless Communications, 2002 and ACM SIGMETRICS Performance Evaluation Review, 2001.
Wi-Fi Certification Wi-Fi Alliance:
The IEEE does not test equipment for compliance with their standards. The non-profit Wi-Fi Alliance was formed in 1999 to fill this void — to establish and enforce standards for interoperability and backward compatibility, and to promote wireless local-area-network technology. As of 2010, the Wi-Fi Alliance consisted of more than 375 companies from around the world. The Wi-Fi Alliance enforces the use of the Wi-Fi brand to technologies based on the IEEE 802.11 standards from the IEEE. This includes wireless 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 limited wide area network (WAN) connections. Manufacturers with membership in the Wi-Fi Alliance, whose products pass the certification process, gain the right to mark those products with the Wi-Fi logo.
Specifically, the certification process requires conformance to the IEEE 802.11 radio standards, the WPA2 and WPA3 security standards, and the EAP authentication standard. Certification may optionally include tests of IEEE 802.11 draft standards, interaction with cellular-phone technology in converged devices, and features relating to security set-up, multimedia, and power-saving. Not every Wi-Fi device is submitted for certification. The lack of Wi-Fi certification does not necessarily imply that a device is incompatible with other Wi-Fi devices.The Wi-Fi Alliance may or may not sanction derivative terms, such as Super Wi-Fi, coined by the US Federal Communications Commission (FCC) to describe proposed networking in the UHF TV band in the US.