Analysis of Terrestrial FSO Link Performance Considering Different Fog Conditions and Internal Parameters of the System

Free space optical communication being one of the effective technologies has higher signal bandwidth and less power for transmission. Atmosphere is used as a communication channel; due to which atmospheric turbulence occurs leading to degradation in the performance of the communication system. The atmospheric turbulence analysed here is the effect of fog attenuation on performance of FSO link. Data for two months i.e January and November for Delhi region have been analysed and simulated using Kim's model. Q-factor has been analyzed by varying the transmission power and range of the FSO system. The simulation results show that for error free transmission of data during the fog months, the transmitting power between 25-35 dBm is recommended to be used for the optimal transmission range from 6-8 Km. Internal parameters on which the performance of the FSO communication depends are divergence angle, wavelength, transmission bandwidth etc. The purpose is to optimize these factors to achieve the maximum output and throughput. In this paper FSO model has been designed using PIN and APD photodiode at receiver's side. Using the model, Q-Factor has been estimated for different beam divergences and wavelengths at varying bit rates. The results have been compared and analyzed for the two types of photodiodes.