Securing Untrusted Full-Duplex Relay Channels in the Presence of Multiple External Cluster-Based Eavesdroppers

TL;DR

This paper proposes a physical layer security scheme for wireless networks with untrusted full-duplex relays and multiple external eavesdroppers, using artificial noise and jamming techniques to enhance confidentiality.

Contribution

It introduces a novel security approach employing artificial noise and relay jamming tailored for untrusted FD relays with cluster-based eavesdroppers, based solely on legitimate channel information.

Findings

Optimal power allocation depends on the number of antennas in eavesdropper clusters.

Artificial noise and jamming improve security against colluding eavesdroppers.

The scheme effectively maintains secure communication in untrusted relay scenarios.

Abstract

This letter investigates the physical layer security in a wireless cooperative network where communication is assisted by a full-duplex (FD) untrusted relay in the presence of multiple external eavesdroppers. A cluster-based colluding eavesdropping setting is considered, where illegitimate nodes with common interests are grouped in a cluster. In order to confuse the different eavesdropping clusters, we consider artificial-noise-aided beamforming at the source node. Moreover, FD relay jamming is adopted to improve the system's security. To maintain secure communications against the untrusted relay node, a FD destination jamming scheme is adopted. Our proposed scheme is designed based on the channel state information of the legitimate nodes only. Numerical results show that the optimal power allocation factor between data and artificial noise depends on the total number of antennas of the different colluding eavesdropping clusters.