This paper analyzes the performance of coherent free-space optical (FSO)
system employing the switch-and-stay (SSC) dual diversity receiver. The
intensity fluctuations of the optical signal are modeled by Gamma-Gamma
distribution, being caused by atmospheric turbulence. In addition, pointing
errors are taken into account. Novel analytical expressions for the outage
probability are derived. The general scenario of unbalanced average
signal-to-noise ratios (SNRs) of independent and identically distributed SSC
branches is considered, which is further simplified to the balanced SNR case.
The effects of various system and channel parameters are investigated and
discussed.