**6. Conclusions**

18 Will-be-set-by-IN-TECH

**Figure 6.** Outage Probability of MIMO FSO systems employing EGC and operating over i.i.d G − G

**Figure 7.** ABEP of MIMO FSO systems employing EGC and operating over i.i.d G − G fading channels

*<sup>n</sup>* <sup>=</sup> 1.7 <sup>×</sup> <sup>10</sup>−14m−2/3 and *<sup>D</sup>*/*<sup>L</sup>* <sup>→</sup> 0)

as a function of the average electrical SNR, (*λ* = 1550nm, *C*<sup>2</sup>

fading channels as a function of the inverse normalized outage threshold, (*λ* = 1550nm,

*C*2

*<sup>n</sup>* <sup>=</sup> 1.7 <sup>×</sup> <sup>10</sup>−14m−2/3 and *<sup>D</sup>*/*<sup>L</sup>* <sup>→</sup> 0)

In this chapter we presented a thorough performance analysis of FSO communication systems using spatial diversity over G − G distributed atmospheric turbulence channels. We obtained accurate approximated closed-form expressions and rapidly convergent infinite series representations for the average bit error probability and the outage probability of SIMO and MIMO FSO systems. Our results demonstrated that significant performance gains can be obtained when multiple apertures at the transmitter and/or receiver are used.
