Performance Analysis of FSO System for Advanced Modulation Formats Under Different Weather Conditions

Over the last few decades the Free Space Optics (FSO) communication is being preferred over the other established technologies such as RF (Radio Frequency) systems for voice and data communication. The FSO communication has many advantages such as high bandwidth, license free technology, ease of deployment and high data rates. In spite of these advantages, it could not gain much popularity in commercial use because of being a light based technology. The light beam travelling through the free space gets affected by different weather conditions like rain, haze and fog etc. which leads to beam divergence and scattering of the optical signal. In this paper we have evaluated the BER and Q-Factor for different modulation formats (CSRZ, MDRZ and DRZ) under various weather conditions. From the results, it has been observed that as atmospheric condition changes from clear weather to haze, rain and fog, link distance range decreases from 3km to 1km, and among the 3 modulation formats CSRZ has the best performance in terms of Q factor and BER for all the weather conditions.