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