These are the most widely used computer networks, used globally in home and small office networks to link devices and to provide Internet access with wireless routers and wireless access points in public places such as coffee shops, restaurants, hotels, libraries, and airports.
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. As of , [update] the Wi-Fi Alliance consisted of more than companies from around the world. Wi-Fi uses multiple parts of the IEEE protocol family and is designed to work well with its wired sibling, Ethernet. Compatible devices can network through wireless access points with each other as well as with wired devices and the Internet.
Wi-Fi most commonly uses the 2. Channels can be shared between networks, but, within range, only one transmitter can transmit on a channel at a time. Wi-Fi's radio bands work best for line-of-sight use. Many common obstructions, such as walls, pillars, home appliances, etc. The range of an access point is about 20 m 66 ft indoors, while some access points claim up to a m ft range outdoors.
Hotspot coverage can be as small as a single room with walls that block radio waves or as large as many square kilometers using many overlapping access points with roaming permitted between them.
Over time, the speed and spectral efficiency of Wi-Fi have increased. As of , [update] some versions of Wi-Fi, running on suitable hardware at close range, can achieve speeds of 9. A ruling by the U. Federal Communications Commission released parts of the ISM bands for unlicensed use for communications. In in Australia, a team of scientists began working on wireless LAN technology. The first version of the This was updated in with The major commercial breakthrough came with Apple Inc.
