QAM and PSK OFDM RoFSO Over $M$-Turbulence Induced Fading Channels

Free-Space Optical (FSO) technology can effectively transfer multiple radio-frequency signals, and this new technique is commonly referred in the technical literature as radio on FSO (RoFSO). In the present study, we investigate the evaluation of an RoFSO scenario employing the orthogonal frequency-division multiplexing scheme. Both phase shift keying and quadrature amplitude modulation (QAM) formats are considered, and the performance is investigated over the weak to strong atmospheric turbulence regime characterized by the recently launched Málaga or $M$-distribution probability density function (pdf). This pdf acts as a unifying statistical model, which incorporates several common irradiance scintillation distributions extensively used by researchers working in the FSO area. We particularly obtain useful mathematical expressions of some critical metrics, i.e., the average bit error rate (BER) and the probability of outage. Proper numerical results are also provided and depicted using suitable graphs to verify the accuracy of the derived expressions.