Design a Hybrid FSO/RF Communication System and its Performance Evaluation

Nowadays, free space optical (FSO) signals and high radio frequency (RF) are considered effective solutions for improving both the capacity and the coverage area of wireless communication systems. However, the transmission performance of the FSO link is significantly affected by some atmospheric turbulence. It may be pointing to errors in various weather conditions, while high RF access networks, represented by millimeter-wave (mm-wave), experience low data rates and moderately high delays. In this research, a design of a hybrid FSO/RF system has been proposed and investigated to ensure a reliable communication link, where an RF channel supports the FSO channel. The system assumes that one channel remains available at any working period, preventing interruptions in the hybrid system. As a result, the transmitter would be consuming a lower amount of power, and the receiver system design would be simplified, eliminating the need for complex combination techniques to extract data. The quality of the proposed hybrid system is investigated based on measuring the minimum received power. The performance of the FSO link is evaluated by calculating bit error rate (BER) and quality (Q) factors under different weather conditions, considering variable FSO channel ranges up to 1 km. The proposed hybrid link design is tested with the Optiwave photonics program and MATLAB simulation tools. The obtained results showed that this hybrid system can achieve a good performance and it can cover a wireless link up to 1km successfully.