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Selectivity is a measure of the performance of a radio receiver to respond only to the radio signal it is tuned to (such as a radio station) and reject other signals nearby in frequency, such as another broadcast on an adjacent channel.
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
Frequency diversity: The signal is transmitted using several frequency channels or spread over a wide spectrum that is affected by frequency-selective fading. Later examples include: Later examples include:
Frequency (subcarrier) interleaving increases resistance to frequency-selective channel conditions such as fading. For example, when a part of the channel bandwidth fades, frequency interleaving ensures that the bit errors that would result from those subcarriers in the faded part of the bandwidth are spread out in the bit-stream rather than ...
The following channels are the principal multi-terminal channels first introduced in the field of information theory [citation needed]: A point-to-multipoint channel , also known as broadcasting medium (not to be confused with broadcasting channel): In this channel, a single sender transmits multiple messages to different destination nodes.
As an example of how the 2D spreading on VSF-OFCDM works, if you take the first data symbol, d 0, and a spreading factor in the time domain, SF time, of length 4, and a spreading factor in the frequency domain, SF frequency of 2, then the data symbol, d 0, will be multiplied by the length-2 frequency-domain PN codes and placed on subcarriers 0 ...
The feedback capacity is known as a closed-form expression only for several examples such as the trapdoor channel, [14] Ising channel, [15] [16]. For some other channels, it is characterized through constant-size optimization problems such as the binary erasure channel with a no-consecutive-ones input constraint [ 17 ] , NOST channel [ 18 ] .
Selective calling prevents the user from hearing others on a shared channel. It does not eliminate interference from co-channel users (other users on the same radio channel). If two users try to talk at the same time, the signal will be affected by the other party using the channel. Some selective calling systems experience falsing. In other ...