WLAN - Basic Knowledge

WLAN - Wireless Local Area Network - means technology which allows to build wireless data networks with satisfactory parameters and quite large range of operation at a comparatively low cost. Additional advantage of this technology is short time needed for its implementation.

Potentiality of WLAN:

* wireless access to local network in home, office, business etc.

* wireless access to the Net in public space, e.g. in airports, stations, cafes etc. (hot-spot)

* wireless point-to-point links (connecting LAN networks, telemetry, remote control, remote monitoring)

* wireless access to the Internet (both in cities and in the country)

* emergency communications link (duplication of wired network)

Standards:

- 802.11a - in 5 GHz band: 5.150 - 5.350 GHz and 5.470 - 5.725 GHz, transfer rate up to 54 Mbps;
- 802.11b - in 2.4 GHz band: 2.4 - 2.483 GHz, transfer rate up to 11 Mbps;
- 802.11g - in 2.4 GHz band: 2.4 - 2.483 GHz, transfer rate up to 54 Mbps;

There are also more standars in use:

- 802.11f - IAPP - Inter Access Point Protocol - for cooperation between access points;
- 802.11i - standard defining new security methods in wireless networks;
- 802.11n - standard for transmitting multimedia in homes using MIMO technology, up to 300 Mbps;
- 802.11e - standard defining QoS - support for high quality of services;
- 802.16 - WiMax standard for backbone networks of high capacity.

Wireless network range

It should be realized that the range of a wireless network depends on many factors. We can have an influence on some of them and the rest is unknown. The range of wireless network depends on:

- output power
- cable attenuation
- gain of antennas
- sensitivity of devices
- attenuation between antennas
- interferences from other devices
- influence of physical barriers (walls, floors, trees)

So, if we want to know what would be the effective range of our network we have to gather the information mentioned above and carry out simple calculations showed in the further part of this self-help book.

For more details you can search here:

http://www.dipol.com.pl/self-help_book_for_wlan_installers-providers_bib86.htm

more topic at http://info-tech.uni.cc