Capacities for Long-Distance Free-Space Optical Links Under Beam Wander Effects

The performance of the long-distance horizontal free-space optical (FSO) communication link under beam wander effects is studied from the perspective of information theory. Based on the newly proposed beam wander model and strong fluctuation theory, the influence of beam wander is directly included in the scintillation and then the statistical model for intensity fading is presented. The impact of beam wander on the average and outage capacities of the FSO link is investigated, showing that an optimum transmitter beam radius can be selected to make the system achieve maximum average capacity and minimum probability of capacity outage.