Alamouti-type STBC for subcarrier intensity modulated wireless optical communications

We study the error rate of a subcarrier intensity modulated multiple-input multiple-output wireless optical communication system employing phase-shift keying and Alamouti code. Closed-form error rate expressions are derived using a moment generating function approach with a series expansion of the modified Bessel function. Truncation error analysis and asymptotic error rate analysis are also presented. Our asymptotic analysis shows that the diversity order of the system depends only on the smaller channel parameter. The numerical results demonstrate that our series solutions are efficient and highly accurate.