Editing Path loss (section)

==Loss exponent==
{{Unreferenced section|date=August 2017}}
{{main|Log-distance path loss model}}
In the study of wireless communications, path loss can be represented by the path loss exponent, whose value is normally in the range of 2 to 4 (where 2 is for propagation in [[free space]], 4 is for relatively lossy environments and for the case of full [[specular reflection]] from the earth surface&mdash;the so-called flat earth model). In some environments, such as buildings, stadiums and other indoor environments, the path loss exponent can reach values in the range of 4 to 6. On the other hand, a tunnel may act as a [[waveguide]], resulting in a path loss exponent less than 2.

Path loss is usually expressed in [[decibel|dB]]. In its simplest form, the path loss can be calculated using the formula

:<math>L = 10 n \log_{10}(d)+C</math>

where <math>L</math> is the path loss in decibels, <math>n</math> is the path loss exponent, <math>d</math> is the distance between the transmitter and the receiver, usually measured in meters, and <math>C</math> is a constant which accounts for system losses.