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Rayleigh fading is a statistical model for the effect of a 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 fade, according to a Rayleigh distribution — the radial component of the sum of ...
Frequency-selective time-varying fading causes a cloudy pattern to appear on a spectrogram. Time is shown on the horizontal axis, frequency on the vertical axis and signal strength as grey-scale intensity. In wireless communications, fading is the variation of signal attenuation over
The Nakagami distribution is relatively new, being first proposed in 1960 by Minoru Nakagami as a mathematical model for small-scale fading in long-distance high-frequency radio wave propagation. [4] It has been used to model attenuation of wireless signals traversing multiple paths [ 5 ] and to study the impact of fading channels on wireless ...
In environments with many MPCs, each with distinct amplitudes and random phases, small-scale fading often adheres to a Rayleigh distribution. [5] Particularly in Air-to-Air (A2A) and Air-to-Ground (A2G) channels, where Line-of-Sight (LOS) propagation predominates, a Ricean distribution is a more appropriate model. [ 5 ]
Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque ...
In wireless communications, channel state information (CSI) is the known channel properties of a communication link.This information describes how a signal propagates from the transmitter to the receiver and represents the combined effect of, for example, scattering, fading, and power decay with distance.
TWDP models fading due to the interference of two strong radio signals and numerous smaller, diffuse signals. TWDP is a generalized system using a statistical model to produce results. Other statistical methods for predicting fading, including Rayleigh fading and Rician fading, can be considered as special cases of the TWDP model. The TWDP ...
This corresponds to the following non-logarithmic gain model: =, where = / is the average multiplicative gain at the reference distance from the transmitter. This gain depends on factors such as carrier frequency, antenna heights and antenna gain, for example due to directional antennas; and = / is a stochastic process that reflects flat fading.