Attenuation Analysis for Optical Wireless Link Measurements under Moderate Continental Fog Conditions at Milan and Graz

Optical wireless links provide complementary behavior to the existing communication technologies like mmW or RF. It is admitted that the next generation of wireless communication networks (4G systems) will be based on multiple access technologies that will complement each other. Optical wireless is a very adequate access technology for future communication requirements and provides a huge bandwidth to the end user and solves the last mile access problem. However, optical wireless links are subject to degraded performance under different atmospheric conditions like fog, sleet, rain and scintillations etc. Therefore, optical channel characterization in different weather conditions is necessary that will yield a better understanding of the statistics of the optical channel that will fine tune the methods used for the prediction of attenuations and improving the link reliability. In this paper, the influence of moderate continental fog on the FSO links installed in Milan and Graz are presented and analyzed based on signal attenuation measurement results. Conclusions are drawn of these results in comparison with attenuations estimated analytically using Mie scattering and modified gamma distribution.