Performance of QPSK modulation for FSO geo-synchronous satellite communication link under atmospheric turbulence

Abstract

In recent years, free space optical (FSO) communication has gained a considerable interest amongst the researchers due to certain benefits it has to offer over RF links such as availability of large unlicensed bandwidth, high data rates, negligible electromagnetic interference, ease of installation etc. However the conventionally used FSO systems use On-Off Keying (OOK) as the modulation technique. Such a link requires high levels of transmit power. In this paper, we have suggested the use of QPSK modulation technique which allows us to reap the benefits of coherent detection. Our calculations show that QPSK is more inert to the changes in atmospheric conditions like temperature, air pressure, humidity, aerosol concentration etc. � 2013 IEEE.