Paper Title
Study Of Link Availability And Data Rate Analysis In FSO-OFDM System

Abstract
Abstract— Free Space Optics (FSO) is also called Wireless Optics that is gaining momentum among researchers to improve the data rate of the access points in broad band connectivity. Increase in the demand for high data rate can be met by the use of hybrid techniques like Orthogonal Frequency Division Multiplexing based FSO that combines the OFDM with FSO system. OFDM symbol modulates the light which passes through free space to provide the point – point link. The FSO link is affected by various predictable and unpredictable phenomena that cause variation in the light passing through it. In OFDM based FSO system, besides the climatic condition caused variation in the signal power, it also varies from symbol to symbol. Thus link availability of OFDM based FSO system depends not only on the atmospheric condition, but also on the signal power of the symbol. Once the attenuation due to the climatic condition is predicted and taken care in the link margin expression, the link availability can be improved by the proper choice of threshold power at the receiver. From the simulation of the OFDM based FSO system, it is observed that the link availability is 99. 3%, 98.3% and 99 % under the influence of three climatic conditions viz. summer, winter and rainy condition respectively. The data rate analysis helps in the selection of transmitter with narrow beam width of 1mrad, receiver with sensitivity of -45dBm over a transmission distance of 1km for the hybrid technique.