selective fading

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selective fading

[si′lek·tiv ′fād·iŋ]
(communications)
Fading that is different at different frequencies in a frequency band occupied by a modulated wave, causing distortion that varies in nature from instant to instant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The performance is decline because Delay Spread: Frequency Selective Fading causing the Inter-Symbol Interference (ISI) and the signal power to be weakened and because Doppler Shift causing the frequency signal wave to be changed or distorted.
However based on the time delay spread small scale fading can be categorized as flat fading and frequency selective fading. As per Doppler spread small scale fading can be categorized as fast fading and slow fading.
Orthogonal frequency division multiplexing (OFDM) as a multi-carrier communication technique, has been adopted in many applications because of its performance against the broadband mobile wireless communications' frequency selective fading effect [1].
This makes the power line channel cause multipath effect, and the transmission characteristics show a certain frequency selective fading.
OFDM is appealing techniques for wireless high-rate information transmission with high bandwidth efficiency because of minimizing impact over frequency selective fading channels .OFDM have a point of interest in that modulation and demodulation can be done by utilizing the Inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (FFT) operations, which are computationally productive.
Several papers have analysed performance of DS-CDMA systems based on cooperative diversity in which direct transmission is considered in addition to two-hop relaying over different fading channels such as Rayleigh, Nakagamim and frequency selective fading channels [8]-[17].
WOFDM performs channel modeling through accurate characterization of time variant and frequency selective fading channels [24].
However, suffering from the frequency selective fading of the dispersive wireless channel, some subchannels may face deep fading and degrade the overall system performance.
The first is interference caused by echoes exceeding the guard time and the second is frequency selective fading when the symbol duration of each subcarrier is not long enough.
Figure 2 shows an example of Rayleigh fading as well as Rician fading channel responses for frequency flat as well as frequency selective fading.
SC-FDE is frequency domain equalization technique used for reduction of frequency selective fading effects in LTE uplink.

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