Performane evaluation of the Free Space Optical (FSO) communication with the effects of the atmospheric turbulances

Abstract

Free space optical (FSO) communication has emerged as a viable technology for broadband wireless applications which offers the potential of high bandwidth capacity over unlicensed optical wavelengths.Atmospheric turbulence has a significant impact on the quality of a laser beam propagating through the atmosphere over long distances. For optical wireless communication systems, most frequently used system is Intensity Modulated Direct Detection (IM/DD) system. For FSO systems, although the power efficiency is inferior to PPM, OOK encoding is more commonly used due to its efficient bandwidth usage and robustness to timing errors. In the presence of atmospheric turbulence, the received signal exhibits random intensity fluctuations which increase the BER. In this dissertation the characteristics and properties of several important design parameters are discussed with the modulation analysis and the link performance evaluated under considering the effects of the atmospheric turbulence's which is the great challenges for the FSO.