FSO links with diversity pointing errors and temporal broadening of the pulses Over weak to strong atmospheric turbulence channels

Free space optical (FSO) communication systems show a growing evolution in the commercial and the research field, due to the huge information capacity they.provide along with the unlicensed and secure data transmission they can support. However, several destructive effects, such as the atmospheric turbulence and attenuation, the longitudinal pulse broadening due to the time dispersion, the spatial jitter which caused by the pointing errors between the trans -receivers, among others, mitigate their performance characteristics. Thus, for the improvement of the FSO communication systems' performance, many techniques have been proposed, studied and used. In this work, we present a performance study and we derive closed form mathematical expressions for the estimation of the probability of fade for On Off keying FSO communication systems which use Gaussian longitudinal pulses as information bit carriers, with reception diversity, over gamma gamma or gamma modelled, atmospheric turbulence channels taking into account the pointing errors and the group velocity dispersion (GVD) effect which, affects significantly the systems performance characteristics, especially for long link lengths and high data rate transmission. Finally, the derived mathematical expressions are used in order to present performance results, using common parameter values for channel's and systems' characteristics. (C) 2015 Elsevier GmbH. All rights reserved.