Optimal Power Allocation for Enhancing Physical Layer Security in Opportunistic Relay Networks in the Presence of Co-Channel Interference

In this paper, the impact of co-channel interference (CCI) on the secrecy performance of the dual-hop decode-and-forward relaying network is investigated. First, the security-reliability trade-off (SRT) analysis is studied for conventional single-hop networks under a single passive eavesdropper attack. Then, the SRT analysis is investigated to the opportunistic relay selection (ORS) model in the presence of independent and identically distributed (i.i.d.) interfering signals. Moreover, the proposed work enhances physical layer (PHY) security performance of ORS model using cooperative jamming techniques (CJ-ORS). For this purpose, new closed-form expressions are derived for intercept probability and outage probability of CJ-ORS model in the presence of interference over Rayleigh fading channels. A power allocation optimization problem is formulated and solved for enhancing the system security. The derived analytical formulas herein are supported by numerical and simulation results to clarify the main contributions of the paper.