Performance analysis of FSO communication with aperture averaging under varying atmospheric turbulence Regimes

The performance of ground to satellite Free Space Optical (FSO) communication link is degraded due to the presence of atmospheric turbulence that causes fluctuations in both intensity and phase of the received optical signal. In this paper, bit error rate (BER) performance of FSO link using low-overhead technique i.e., aperture averaging is investigated for coherent (sub-carrier BPSK) and non-coherent (OOK) modulation schemes in weak atmospheric turbulence channel. RSoft OptSim software is used to design communication links for these modulations and simulation is done in the block mode. It is seen that aperture averaging along with coding schemes provides robust mitigation strategies. It is observed that sub-carrier BPSK modulation outperforms the other modulation scheme i.e., OOK in terms of less probability of error rate if all other parameters are kept constant or varied accordingly. Also, sensitivity of modulation schemes towards different channel parameters is observed for aperture averaging.