On the Performance of DF based Mixed Triple-Hop RF-FSO-RF Cooperative System

In this work, we analyze the performance of decode-and-forward (DF) based triple-hop radio frequency-free space optical-radio frequency (RF-FSO-RF) communication system. The mixed RF-FSO-RF system derive application, where the FSO link can be used to provide high speed connectivity between the two RF networks. The RF links are characterized by Nakagami-m fading and the FSO link is characterized by path loss, Gamma-Gamma distributed turbulence and pointing errors. For this asymmetric triple hop communication system, new closed form mathematical expressions are obtained for statistical characteristics of end-to-end signal-to-noise ratio (SNR), i.e., cumulative distribution function and probability density function. Using these expressions, novel closed form expressions are derived for the outage probability and the average bit error rate of various modulation techniques. Numerical results show the effect of fading, turbulence, and pointing errors on the performance of the considered cooperative system.