Effects of multiple scattering due to atmospheric water particles on outdoor Free Space Optical links

Free Space Optics (FSO) systems, operating at near infrared or optical frequencies, represent an attractive possibility for wireless communications. Carrier wavelength and narrow beams ensure high data rates with reduced error rates and safety of communications. Nevertheless, their sensitivity to atmospheric conditions limits outdoor FSO applications. Fog droplets, raindrops and snowflakes, may introduce severe path attenuation, which drastically reduces the channel availability up to the channel interruption. In this respect, much work is still required, both in model and measurements perspectives. This work is devoted to a model analysis of multiple scattering effects on the FSO communication channel due to atmospheric hydrometeors. Within this framework, a parametric model is introduced to simulate and characterize scattering behavior of droplets. Several hydrometeor classes are analyzed and discussed, including fog droplets, raindrops, snowflakes and graupel particles.