In a presentation by Mohsen Kavehrad (FIEEE) of the Department of Electrical Engineering, Center for Information and Communications Technology Research (CICTR) at Pennsylvania State University (University Park, Pennsylvania, USA) discussed Free Space Optics (FSO) technology advances on July 12, 2011 in Toronto, Ontario (Canada).
The following summary was provided regarding Free Space Optics (FSO) communication links in clouds and turbulence:
- Cloud Monte-Carlo Ray Tracing (MCRT) speeded up by Markov chain scattering phase model is a great numerical evaluation tool.
- Turbulence modeling via different phase screens used and compared based on accuracy and computational complexity.
- Effects of clouds and aerosols can be practically modeled only with the LoS (line-of-sight) component of the scattered beam due to link and receiver geometry, resulting in a time-varying attenuation coefficient.
- Turbulence-induced amplitude variations can be modeled by Lognormal fading for small apertures.
- For larger apertures, aperture-averaging can significantly reduce intensity fluctuations of received light.
- Under increased turbulence, MIMO (Multiple-Input Multiple-Output) systems are more robust to PSF distortions and intensity fading.
- With adequately spaced smaller apertures, paths correlation affects MIMO gain minimally, given adaptive optics.
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