A WLAN's transmission range is affected by the characteristics of the frequency band it uses; by government regulations limiting transmission power in that band; by electromagnetic conditions at the site (levels of radio-wave obstruction, absorption, reflection, and interference); and by the kinds of antennas used. There is tremendous variation, both in vendors' claims regarding transmission range and in the effective range achieved in different installations.
WLAN Speed Switching
Most WLAN devices can automatically switch to a lower speed when signals deteriorate and return to higher speeds when signals improve. On an indoor 802.11b WLAN, it is usually possible to maintain a speed of 11 Mbps at distances up to 100 feet (33 meters). In some cases this speed can be maintained at up to 130 feet (40 meters).