A time-diversity scheme for wireless optical links over exponentially modeled turbulence channels

The wireless optical communication systems attract significant research and commercial interest the last few years due to their capability of achieving wireless communications with very high and secure data rate transmission with simultaneous low installation and operational cost, without need of licensing, for relatively short propagation distances. On the other hand, due to the wireless information transmission, the influence of the atmospheric conditions, in the area between the transmitter and the receiver, at the availability and performance of these systems is very strong. A very significant phenomenon, which increases the system's efficiency, is the atmospheric turbulence. Many methods have been proposed in order to overcome this increasing and the diversity schemes compose a very efficient solution. In this work, we investigate a time-diversity scheme for free space optical channels under strong turbulence conditions modeled with the negative exponential distribution. We extract closed form mathematical expressions for the estimation of the outage probability, the average bit error rate and the maximum effective bit rate, which are metrics for the evaluation of link's availability and performance respectively. Finally, we present numerical results for many practical cases.