Wireless LAN (WLAN) and Wi-Fi

A wireless local area network (WLAN) connects computers and other devices to a network using radio waves rather than cables. The most common form is known by the Wi-Fi name. A WLAN typically centres on an access point, a device that communicates with nearby wireless devices and bridges them to a wired network and, through it, to the internet. Devices within range of an access point can join the network and move freely without a physical connection, which is the main advantage of wireless networking.

WLANs operate in unlicensed radio bands, frequency ranges that may be used without an individual licence provided equipment meets power and behaviour limits. Because these bands are shared by many devices and technologies, WLAN equipment must tolerate interference. It does so using spread-spectrum and multi-carrier modulation techniques, error checking, and protocols that retransmit data that arrives corrupted. A protocol governs when each device may transmit, so that several devices sharing one channel do not constantly talk over one another.

WLAN is one of several wireless technologies that serve different ranges and purposes. Bluetooth links personal devices over a few metres, using frequency hopping to resist interference. Cellular technologies such as GSM and the code-division and time-division methods used in mobile networks provide wide-area coverage for phones. The Global Positioning System (GPS) uses signals from satellites for location finding rather than two-way communication. Each technology trades off range, data rate and power consumption to suit its intended use, and many devices contain several of them at once.

Frequently asked questions

What is an access point in a WLAN?

It is a device that communicates with nearby wireless devices and bridges them to a wired network and the internet, forming the hub of a typical wireless LAN.

Why does WLAN use unlicensed bands?

Unlicensed bands can be used without an individual licence, which made Wi-Fi widely deployable, though equipment must tolerate interference from other devices sharing those frequencies.

How does WLAN differ from Bluetooth?

WLAN connects devices to a network over tens of metres at higher data rates, while Bluetooth links personal devices over a few metres at lower power and rate.