Performance Analysis of Subcarrier-based Maximal-Ratio Combining (MRC) Algorithm for Intensity Modulation and Direct Detection (IM/DD) Free Space Optical Communication (FSOC)

We explore subcarrier-based maximal-ratio-combining (MRC) in intensity-modulation-and-direct-detection (IM/DD) free-space-optical-communication (FSOC). We analyze and address the challenges posed by the correlated beating noise arising from the square law detection, demonstrating how the MRC processing gain decreases with increasing received power.