Error performance of SIMO and MISO FSO links over weak and strong turbulent channels

In spite of the several technical advantages of a free-space optical (FSO) communication, the performance of a FSO link could be severely degraded due to atmospheric turbulence, which causes random fluctuations of the phase and the amplitude of the received signal. The simultaneous use of multiple transmit/receive apertures (MIMO) can mitigate the fading effects, that is particularly crucial for strong turbulent channels, but SIMO and MISO schemes have less complexity and more applicability than the MIMO system. So in this paper, we investigate the performance of symbol-error-rate (SER) in FSO links with Q-Ary PPM modulation in these schemes, both in the weak and strong turbulence conditions. It is shown that in a defined received energy per bit, employing diversity and adding the number of resources in receiver end is more efficient than the transmitter both in the weak and strong atmospheric turbulence scenarios.