Generalized performance analysis of mixed RF/FSO systems

We investigate the performance of dual-hop fixed-gain amplify-and-forward relaying systems over Nakagami-m and double generalized Gamma fading channels with pointing error for mixed radio frequency/free space optical (RF/FSO) wireless systems. Our analysis generalizes several previous results, since it considers general fading channels and both detection methods in FSO systems. In particular, exact expressions for the end-to-end outage probability and bit error probability are derived in dosed-form, while useful expressions are presented for the asymptotically high signal to noise ratio (SNR) regime. The numerical results provide important physical insights into the implications of model parameters on the system performance; for instance, it is demonstrated that in all cases under consideration, the lowest outage and bit error rates would not guarantee only by decreasing the pointing error and using the heterodyne detection and not increasing the RF link parameters.