Journal Homepage: www.ijcst.org

Abstract — In spite of the several technical advantages of a free-space optical (FSO) communication, atmospheric turbulence can severely degrade the performance of a FSO link, because it creates random fluctuations in the phase and the amplitude of the received signal. The simultaneous usage of multiple transmit/receive apertures (MIMO) can mitigate the fading effects, that is particularly crucial for strong turbulent channels. However comparing to SIMO and MISO schemes, MIMO system it has more complexity and less applicability. In this paper, we investigate the performance of symbol-error-rate (SER) and outage capacity in FSO links with Q-Ary Pulse Position Modulation (PPM) in these schemes, both in the weak and strong turbulence conditions. Our results show that in a defined received energy per bit, employing diversity and adding the number of resources at the receiver end is more efficient than the transmitter both in the weak and strong atmospheric turbulence scenarios