In communications, the additive white Gaussian noise (AWGN) channel is one in which the only impairment is the linear addition of wideband Gaussian noise with a constant spectral density (expressed as watts per hertz of bandwidth). There is no fading, frequency selectivity, interference, nonlinearity or dispersion.
Wideband Gaussian noise comes from many natural sources, such as the thermal vibrations of atoms in antennas, "black body" radiation from the earth and other warm objects, and from celestial sources such as the sun.
The AWGN channel is a good model for many satellite and deep space communication links. It is not a good model for most terrestrial links because of multipath, terrain blocking, interference, etc.
The AWGN Channel block adds white Gaussian noise to a real or complex input signal.
If the variance is a vector whose length is the number of channels in the input signal, then each element represents the variance of the corresponding signal channel.
The variance of each of the quadrature components of the complex noise is half of the calculated or specified value.
In communications, the additive white Gaussian noise (AWGN) channel model is one in which the only impairment is the linear addition of wideband or white noise with a constant spectral density (expressed as watts per hertz of bandwidth) and a Gaussian distribution of amplitude.
It is not a good model for most terrestrial links because of multipath, terrain blocking, interference, etc. However for terrestrial path modeling, AWGN is commonly used to simulate background noise of the channel under study, in addition to multipath, terrain blocking, interference, ground clutter and self interference that modern radio systems encounter in terrestrial operation.
In serial data communications, the AWGN mathematical model is used to model the timing error caused by random jitter (RJ).
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