Transmission Analysis of OFDM-Based Wireless Services Over Turbulent Radio-on-FSO Links Modeled by Gamma–Gamma Distribution

Radio-on-free space optical (RoFSO) communication systems are rapidly gaining popularity as an efficient and cost-effective means of transferring high data rates and radio frequency (RF) signals with the same capacity as optical fiber. However, the performance of those systems depends strongly on the atmospheric conditions and the nonlinear characteristics of the optical link. In this paper, we introduce an analytical model for the transmission of orthogonal frequency division multiplexing (OFDM)-based signals over freespace optics (FSO) links. Further, we derive a closed-form bit error probability (BEP) and outage probability expressions, taking into account the optical noises, the laser diode nonlinear distortion, and the atmospheric turbulence effect on the FSO channel modeled by the gamma-gamma distribution. This paper reports the most significant parameters that degrade the transmission performance of the OFDM signal over FSO links and indicates the cases that provide the optimal operating conditions for the link. The obtained results can be useful for designing, predicting, and evaluating the RoFSO system's ability to transmit wireless services over turbulent FSO links under actual conditions.