Opportunistic Relay Selection over Generalized Fading and Inverse Gamma Composite Fading Mixed Multicast Channels: A Secrecy Tradeoff

TL;DR

This paper analyzes the secrecy performance of a dual-hop wireless multicast system with relays under complex fading and shadowing conditions, deriving closed-form expressions for key secrecy metrics and exploring tradeoffs to enhance security.

Contribution

It introduces a novel opportunistic relay selection framework considering generalized fading and shadowing, with new analytical secrecy expressions for multicast channels.

Findings

Secrecy measures are derived in closed form for complex fading scenarios.

Tradeoffs between relays, receivers, and eavesdroppers are identified.

System parameters significantly influence secrecy performance.

Abstract

The secrecy performance of realistic wireless multicast scenarios can be significantly deteriorated by the simultaneous occurrence of multipath and shadowing. To resolve this security threat, in this work an opportunistic relaying-based dual-hop wireless multicast framework is proposed in which the source dispatches confidential information to a bunch of receivers via intermediate relays under the wiretapping attempts of multiple eavesdroppers. Two scenarios, i.e. non-line of sight (NLOS) and line of sight (LOS) communications along with the multiplicative and LOS shadowing are considered where the first scenario assumes eta-mu and eta-mu/inverse Gamma (IG) composite fading channels and the latter one follows kappa-mu and kappa-mu/IG composite fading channels as the source to relay and relay to receiver's as well as eavesdropper's links, respectively. Secrecy analysis is accomplished by deriving closed-form expressions of three familiar secrecy measures i.e. secure outage probability for multicasting, probability of non-zero secrecy multicast capacity, and ergodic secrecy multicast capacity. We further capitalize on those expressions to observe the effects of all system parameters which are again corroborated via Monte-Carlo simulations. Our observations indicate that a secrecy tradeoff between the number of relays and number of receivers, eavesdroppers, and shadowing parameters can be established to maintain the admissible security level by decreasing the detrimental influences of fading, shadowing, the number of multicast receivers and eavesdroppers.