Keywords : Fading


Study of WMAN Physical Layer under Fading Channels

Hatem Fahad Frayyeh

Anbar Journal of Engineering Sciences, 2016, Volume 7, Issue 1, Pages 21-31
DOI: 10.37649/aengs.2016.124362

WMAN (wireless metropolitan area network) technology is based on the IEEE 802.16
air interface standard suite, which provides the wireless technology for fixed and
nomadic data access. WMAN employs orthogonal frequency division multiplexing
(OFDM), and supports adaptive modulation and coding depending on the channel
conditions. The objective of this paper is to study the performance of the IEEE 802.16d
WMAN physical layer under Nakagami model as a Multi-path and frequency-selective
fading channel beside the additive white Gaussian noise (AWGN) and Doppler. Finally,
we compared it with the Rayleigh fading model. The transmission bit rate, Probability
of Error ( ) and estimated SNR have been compared under single/multi path
propagation conditions.

Scintillation Effect on Satellite Communications within Standard Atmosphere

Mohammed Ali Hussein

Anbar Journal of Engineering Sciences, 2009, Volume 2, Issue 2, Pages 17-27
DOI: 10.37649/aengs.2009.14227

In satellite communications with frequencies above 10GHz the major problems in radio-wave propagation is signal level attenuation caused by tropospheric scintillation, together with signal level attenuation by rain. There are several methods to measure the magnitude of scintillation. The equations of most of these methods do not include meteorological element. In meantime we can not measure the magnitude of scintillation with elevation angle 5¢ھ-10¢ھ. A prediction method is suggested to measure tropospheric scintillation on earth-space path. It would apply this method to standard atmosphere and we studied the effect of meteorological conditions, frequency, antenna diameter and elevation angle on the magnitude of scintillation.