In this paper, the performance of the dual-hop radio frequency/free space optical (RF/FSO) system based on the amplify-and-forward (AF) and decode-and-forward (DF) relaying schemes is analyzed. The RF link is modeled by Nakagami-m distribution for the multipath fading channel which is a generalized distribution. The FSO link is characterized by Fisher-Snedecor ( \(\mathcal{F}\) ) fading distribution that is valid for all atmospheric turbulence conditions. Operating the intensity modulation direct detection scheme, the unified expression of the cumulative distribution function (CDF) is employed for the instantaneous end-to-end received signal-to-noise ratio (SNR). By utilizing its CDF, a novel mathematical framework to drive the exact closed-form expressions of the outage probability (OP) and the average bit error rate (ABER) with different modulation schemes are calculated for the considered system involving Meijer-G functions. Additionally, to get a deeper understanding, asymptotic expressions for the OP and ABER are also obtained in terms of basic elementary functions. Further, the analytical results collaborate with simulation results which validate the use of the derived expressions. The results revealed that increases in the severity of atmospheric turbulence profoundly degrade the system performance. Furthermore, comparisons between dual-hop RF/FSO systems, hybrid RF/FSO systems, and single FSO systems are presented.
