Performance Analysis of Interference Limited Hybrid FSO/RF Systems

Free Space Optics (FSO) is a promising choice for dealing with high data-rate applications, and it improves reliability by using RF communication as a backup link. In a practical scenario, the RF link is affected by co-channel interference. We investigate the performance of an interference-limited hybrid FSO/RF system. We consider a transmitter $(T_{X})$ and a receiver $(R_{X})$ with threshold-based switching selection at the RX. Atmospheric turbulence, path loss, and pointing errors influence the FSO link, which is modelled using the gamma-gamma distribution, whereas the RF link is modelled using the $\kappa-\mu$ distribution. We have derived the end-to-end symbol error rate and the outage probability for the interference limited system. Results show that interference increases the error rate and degrades the system performance. The impact of interference is high in the lower SNR’s and it is controlled by increasing the Signal to Interference Ratio (SIR) of RF link. To verify the results, Monte carlo simulations are used.