There are no range requirements from IEEE,
the FCC or ETSI, as the range can vary greatly depending on many
factors. Typical ranges for 802.11 may be 30 m (60 ft) for
indoors, and 100 m (300 ft) for outdoor use. As the received
signal strength and/or quality drops, the data rate will also
drop. "Dead spots" (no signal) may occur in certain areas where
heavy attenuation is present (ex: cement walls).
Primary factors that
affect range are:
Frequency: As
radio waves in lower frequencies travel farther than higher
ones, the range of a 5 Ghz AP will be shorter than one in 2.4
Ghz.
Obstacles:
Obstacles such as walls, doors, etc. attenuate radio signals.
Higher frequencies are affected more than lower.
Transmit power:
Signal attenuation:
Convert Watts <> dBm
Calculate Free Space Loss
MHz
Km
OR Miles
dB
Power and Sensitivity:
Output power can vary according to country regulations. Receiver
sensitivity can vary according to equipment manufacturer
specifications. A lower sensitivity value will allow for a
further range. Range can also be increased with high-power
external antennas, on both the AP and user ends (depending on
country laws) as well as enhanced receivers that offer lower
than normal sensitivity values.
Below is an example of the
specifications from a Cisco Aironet 1130AG wireless AP
(*Note: Values may vary by manufacturer):
Routers
transmit power also varies based on the Received Power
Indication (ie: the closer the user is to the AP, the less poer
the AP transmits at):
