Performance analysis of Alamouti scheme in free-space optical communications channel

In this study, the power series expression of the average bit error rate (BER) of the Alamouti scheme is derived in gamma-gamma fading channels using the SIM scheme. According to the analysis, the Alamouti scheme could achieve a high signal-to-noise ratio (SNR) gain of 37 dB in a strong turbulence regime, and also a high SNR gain of 27 dB in a moderate turbulence regime over the no diversity at the BER of 10
⁻⁶
.