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Selective fading or frequency selective fading is a radio propagation anomaly caused by partial cancellation of a radio signal by itself — the signal arrives at the receiver by two different paths, and at least one of the paths is changing (lengthening or shortening).
Diversity is mainly used in radio communication and is a common technique for combatting fading and co ... by frequency-selective fading. Later examples include ...
In multi-carrier communication systems, interleaving across carriers may be employed to provide frequency diversity, e.g., to mitigate frequency-selective fading or narrowband interference. [ 28 ] Example
With transmit diversity, multiple antennas transmit delayed versions of a signal, creating frequency-selective fading, which is equalized at the receiver to provide diversity gain. Since transmit diversity with N antennas results in N sources of interference to other users, the interference environment will be different from conventional ...
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The key idea behind AFH is to use only the "good" frequencies and avoid the "bad" ones—those experiencing frequency selective fading, those on which a third party is trying to communicate, or those being actively jammed. Therefore, AFH should be complemented by a mechanism for detecting good and bad channels.
However, with an increasing number of applications operating in highly mobile environments, the effect of dispersive fading caused by a combination of multi-path propagation and doppler shift is more significant. Over the last decade, research has been done on how to equalize OFDM transmission over doubly selective channels. [25] [26] [27]
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 ...