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Multipath propagation
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<p>In <a href="/facts/Radio_communication/XFr909M2">radio communication</a>, multipath is the <a href="/facts/Radio_propagation/80y1JV4M">propagation</a> phenomenon that results in <a href="/facts/Radio_signal/XmB6WPpF">radio signals</a> reaching the receiving <a href="/facts/Antenna_(electronics)/pGlcXBvc">antenna</a> by two or more paths. Causes of multipath include <a href="/facts/Atmospheric_ducting/dMg19xrx">atmospheric ducting</a>, <a href="/facts/Ionospheric_reflection/7AaWN9Nt">ionospheric reflection</a> and <a href="/facts/Refraction/S8kvSKzM">refraction</a>, and <a href="/facts/Reflection_(physics)/BhcjDs79">reflection</a> from water bodies and terrestrial objects such as mountains and buildings. When the same signal is received over more than one path, it can create <a href="/facts/Interference_(wave_propagation)/lI5f78I4">interference</a> and <a href="/facts/Phase_(waves)/cpGtuVll">phase shifting</a> of the signal. Destructive interference causes <a href="/facts/Fading/RsDwBbdz">fading</a>; this may cause a radio signal to become too weak in certain areas to be received adequately. For this reason, this effect is also known as multipath interference or multipath distortion. </p><p>Where the magnitudes of the signals arriving by the various paths have a distribution known as the <a href="/facts/Rayleigh_distribution/vLFh4zHr">Rayleigh distribution</a>, this is known as <a href="/facts/Rayleigh_fading/ryY9Bm9I">Rayleigh fading</a>. Where one component (often, but not necessarily, a <a href="/facts/Line_of_sight_(telecommunications)/w4xfQd2o">line of sight</a> component) dominates, a <a href="/facts/Rice_distribution/E9tY1XNJ">Rician distribution</a> provides a more accurate model, and this is known as <a href="/facts/Rician_fading/TdD88qhs">Rician fading</a>. Where two components dominate, the behavior is best modeled with the <a href="/facts/Two-wave_with_diffuse_power_fading/y6XnRKxy">two-wave with diffuse power (TWDP)</a> distribution. All of these descriptions are commonly used and accepted and lead to results. However, they are generic and abstract/hide/approximate the underlying physics. </p>