Performance Analysis of a Dual FSO/RF Hybrid Link in the Presence of Malicious Intruder

One of the fundamental issues in the field of wireless communication is security. To overcome this problem, hybrid radio frequency (RF)/free space optical (FSO) link with the presence of an eavesdropper present are modelled and an algorithm is proposed to select the most secure link based on the derived security metrics. The FSO links are modelled using exponential distribution considering different parameter values, thus exhibiting a strong atmospheric turbulent nature of the environment. Divergent environments and channel conditions tend to make the RF and FSO channels behave uniquely and complementary to each other. To attain high data rates along with higher reliability, RF and FSO links are incorporated together to form a hybrid FSO/RF communication system. The proposed algorithm is based on a security metric which is determined by computing the probability of strictly positive secrecy capacity (SPSC). Analytical closed-form expressions of SPSC have been obtained for the proposed system. Further, monte carlo simulations are performed to validate and confer the analytical results.