Wireless Fidelity (Wi-Fi) - page 2
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
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.