Secure Beamforming and Ergodic Secrecy Rate Analysis for Amplify-and-Forward Relay Networks with Wireless Powered Jammer

TL;DR

This paper proposes a novel secure beamforming scheme with a wireless-powered jammer in amplify-and-forward relay networks, achieving higher secrecy rates and providing analytical insights into ergodic secrecy performance.

Contribution

A new secure beamforming method combining energy and information beamforming with a closed-form solution and ergodic secrecy rate approximation for large antenna regimes.

Findings

Proposed beamforming vector outperforms trivial schemes in secrecy rate.

Derived a closed-form solution for the beamforming vector.

Provided a tight approximation for ergodic secrecy rate in large-antenna scenarios.

Abstract

In this correspondence, we consider an amplify-and-forward relay network in which relayed information is overheard by an eavesdropper. In order to confound the eavesdropper, a wireless-powered jammer is also considered which harvests energy from a multiple-antenna source. We proposed a new secure beamforming scheme in which beamforming vector is a linear combination of the energy beamforming (EB) and information beamforming (IB) vectors. We also present a new closed-form solution for the proposed beamforming vector which is shown to achieve a higher secrecy rate as compared to the trivial EB and IB vectors. Moreover, a tight closed-form approximation for the ergodic secrecy rate is also derived for the asymptotic regime of a large number of antennas at the source. Finally, numerical examples and simulations are provided which validate our analytical results.