Editing Rayleigh fading (section)

{{Short description|Radio signal statistical model}}
'''Rayleigh fading''' is a [[statistics|statistical]] [[mathematical model|model]] for the effect of a [[wave|propagation]] environment on a [[radio]] signal, such as that used by [[wireless]] devices.

Rayleigh fading models assume that the magnitude of a signal that has passed through such a [[transmission medium]] (also called a [[communication channel]]) will vary randomly, or [[fading|fade]], according to a [[Rayleigh distribution]] — the radial component of the sum of two uncorrelated [[Gaussian distribution|Gaussian]] [[random variable]]s.

Rayleigh fading is viewed as a reasonable model for [[tropospheric scatter|tropospheric]] and [[ionospheric reflection|ionospheric]] signal propagation as well as the effect of heavily built-up [[urban area|urban]] environments on radio signals.<ref name="proakis">{{cite book|title=Digital Communications|url=https://archive.org/details/digitalcommunica00proa|url-access=registration|edition=3rd|author=John G. Proakis|year=1995|publisher=McGraw–Hill Book Co|location=Singapore|pages=[https://archive.org/details/digitalcommunica00proa/page/767 767–768]|isbn=978-0-07-113814-7}}</ref><ref>{{cite journal|title=Rayleigh Fading Channels in Mobile Digital Communication Systems Part I: Characterization|author=Bernard Sklar|journal=IEEE Communications Magazine|volume=35|issue=7|date=July 1997|pages=90–100|doi=10.1109/35.601747}}</ref> Rayleigh fading is most applicable when there is no dominant propagation along a [[Line-of-sight propagation|line of sight]] between the transmitter and receiver. If there is a dominant line of sight, [[Rician fading]] may be more applicable.  Rayleigh fading is a special case of [[TWDP fading|two-wave with diffuse power (TWDP) fading]].