in this paper, the effects of scintillation phenomena on bit error rate (ber) and signal to noise ratio (snr), which are essential characteristics in free space optical (fso) communication system, are studied. until now various methods have been introduced to decrease ber and increase the link's reliability. optimizing snr is one of the fundamental methods to decrease ber value. intensity fluct...

This paper reports simultaneous observations of ionospheric scintillation during an auroral substorm that were made using an all-sky full-color digital single-lens reflex (DSLR) camera (ASC) and a Global Positioning System (GPS) ionospheric scintillation and total electron content monitor (GISTM) in Tromsø (69.60 N, 19.20 E), Norway. On the night of November 19, 2009, a small substorm occurred ...

The concept of pseudo-Bessel correlated beams is introduced, and their scintillation properties on propagation through turbulence are investigated. By using the Rytov approximation, the scintillation index of pseudo-Bessel correlated beams is formulated in weak turbulence. The study of scintillation is extended into strong turbulence by numeric simulations. It is shown that by choosing an appro...

By using a complex phase screen model for a diffuser located at the transmitter, analytic expressions are developed for the scintillation index of a lowest order Gaussian-beam wave in the pupil plane of the receiver in weak and strong atmospheric conditions. The effect of partial coherence on the scintillation index is analyzed as a function of the propagation distance and the correlation lengt...

Satellite communication channels are affected by ionospheric scintillation phenomenon, causing signal attenuation. This paper presents the performance of a WaveletBased Multi-Carrier Code Division Multiple Access (WBMC-CDMA) under flat scintillation channels, in comparison with the Fourier-Based method. With scintillation, as the scintillation index S4 increases, the performance of communicatio...

Tropospheric scintillation is caused by variations of refractive index due to turbulence. The only meteorological input parameter for two common current scintillation models by Karasawa et al. and by ITU-R is the monthly average of wet part of refractivity Nwet at ground level, which is not directly associated with turbulence. The diurnal correlation betweenNwet and scintillation variance is ve...

The scintillation index is formulated for modified Bessel-Gaussian beams propagating in weakly turbulent media. Numerical calculations applied directly to the derived triple integral show that, for off-axis positions, the modified Bessel-Gaussian beams of higher than zero order scintillate less than Gaussian beams at large input beam sizes and low beam orders with the increasing width parameter...

We examine the correspondence between high latitude ionospheric scintillation measurements made at 250 MHz with the occurrence of 10 MHz HF coherent radar backscatter, on 13 and 14 December 2002. We demonstrate that when the ionospheric intersection point of the scintillation measurements is co-located with significant HF radar backscatter, the observed scintillation, quantified by the S4 index...

Atmospheric turbulence can cause significant performance degradation in free space optical (FSO) communication system. Major effects on the beam such as beam wander and beam scintillation degrades the performance at the receiver. We investigate the impact of diversity technique and aperture averaging technique on the performance of FSO system. Performance evaluation is made in terms of average ...

Measurements of partially spatially coherent infra-red laser beam intensity fluctuations propagating through a hot-air turbulence emulator are compared with visible laser beam intensity fluctuations in the maritime and IR laser beam intensity fluctuations in the terrestrial environment at the United States Naval Academy. The emulator used in the laboratory for the comparison is capable of gener...