| WLAN - Wireless Local Area Network - means | | | | cooperation between access points; |
| technology which allows to build wireless data | | | | - 802.11i - standard defining new security methods in |
| networks with satisfactory parameters and quite | | | | wireless networks; |
| large range of operation at a comparatively low cost. | | | | - 802.11n - standard for transmitting multimedia in |
| Additional advantage of this technology is short time | | | | homes using MIMO technology, up to 300 Mbps; |
| needed for its implementation. | | | | - 802.11e - standard defining QoS - support for high |
| Potentiality of WLAN: | | | | quality of services; |
| * wireless access to local network in home, office, | | | | - 802.16 - WiMax standard for backbone networks of |
| business etc. | | | | high capacity. |
| * wireless access to the Net in public space, e.g. in | | | | Wireless network range |
| airports, stations, cafes etc. (hot-spot) | | | | It should be realized that the range of a wireless |
| * wireless point-to-point links (connecting LAN | | | | network depends on many factors. We can have an |
| networks, telemetry, remote control, remote | | | | influence on some of them and the rest is unknown. |
| monitoring) | | | | The range of wireless network depends on: |
| * wireless access to the Internet (both in cities and in | | | | - output power |
| the country) | | | | - cable attenuation |
| * emergency communications link (duplication of | | | | - gain of antennas |
| wired network) | | | | - sensitivity of devices |
| Standards: | | | | - attenuation between antennas |
| - 802.11a - in 5 GHz band: 5.150 - 5.350 GHz and 5.470 | | | | - interferences from other devices |
| - 5.725 GHz, transfer rate up to 54 Mbps; | | | | - influence of physical barriers (walls, floors, trees) |
| - 802.11b - in 2.4 GHz band: 2.4 - 2.483 GHz, transfer | | | | So, if we want to know what would be the |
| rate up to 11 Mbps; | | | | effective range of our network we have to gather |
| - 802.11g - in 2.4 GHz band: 2.4 - 2.483 GHz, transfer | | | | the information mentioned above and carry out |
| rate up to 54 Mbps; | | | | simple calculations showed in the further part of this |
| There are also more standars in use: | | | | self-help book. |
| - 802.11f - IAPP - Inter Access Point Protocol - for | | | | |