Wireless Fidelity (Wi-Fi) - page 2

WiFi is the marketing name for IEEE802.11, an international standard from the Institute of Electrical and Electronics Engineers (IEEE) for WLAN that operates at up to 300 megabits per second and has a range up to 300 metres outdoors. IEEE802.11a/g, which provides 54Mbps, has become the most popular worldwide standard for setting up WLANs in offices, colleges, homes and is widely available in public spaces. Competing technologies have been abandoned and equipment suppliers are focussed on supply of WiFi. Multi-millions of pounds in R&D and manufacturing capacity is now delivering 802.11n products which run at up to 300Mbps. Laptop computers and netbooks from major PC manufacturers have 802.11n built-in. New appliances such as smart phones are 802.11n compatible e.g. iPhone.

Competition has already driven down the costs of deploying WiFi networks which can now be deployed by businesses to give their employees mobility within the business. Home users are provided with free WiFi kit to extend their DSL or cable broadband Internet access wirelessly to the entire house. In universities and schools a wireless network can allow computers to be integrated more effectively into teaching as classes no longer need to be held in the ICT room.

802.11bgn operate in the 2.4 GHz unlicensed frequency band and are the most popular WiFi standards. 802.11na has also been standardised by the IEEE and provides up to 300Mbps in the 5GHz unlicensed frequency band.

The main measure of 802.11 equipment interoperability is the Wireless Fidelity (WiFi ®) certification program. Administered by the industry group, Wireless Ethernet Compatibility Alliance (WECA), the Wi-Fi logo (registered trade mark of WECA) on a product certifies its interoperability with other products containing the logo. An independent lab, the Agilent/Silicon Valley Networking Lab performs the actual testing.

802.11e or Wireless Multi Media (WMM) provides Quality of Service (QoS) over 802.11a/b/g/n. Large file downloads use most of the bandwidth on a wireless link, which might cause a VoIP call to "break up" or a video stream to "block up". WMM allows users to use real time services such as video streaming and VoIP while web browsing and downloading files. In order for WMM to function correctly, both a compatible Access Point and Client are required. Proxim equipment supplied by Daconi supports WMM.

802.11n is a standard that provides higher speeds than existing wireless systems. It utilises Multiple Input Multiple Output (MIMO) antenna technology to achieve data rates of 300Mbps+, this is achieved by using more of the available wireless spectrum. The standard was approved in 2009. It operates on both 2.4Ghz and 5Ghz bands. Note that a .11n client is required to take advantage of increased data rates.