Secure two-way communication via a wireless powered untrusted relay and friendly jammer

TL;DR

This paper introduces a secure two-way communication system using a wireless powered untrusted relay and friendly jammer, optimizing energy harvesting and jamming to enhance secrecy rates in a three-phase protocol.

Contribution

It presents a novel three-phase two-way secure communication scheme with a closed-form lower bound for ergodic secrecy sum rate, incorporating friendly jamming and energy harvesting.

Findings

The proposed system outperforms traditional one-way communication.

Friendly jamming significantly improves secrecy performance.

Optimal energy harvesting time and relay placement enhance security.

Abstract

In this paper, we propose a self-dependent two-way secure communication where two sources exchange confidential messages via a wireless powered untrusted amplify-and-forward (AF) relay and friendly jammer (FJ). By adopting the time switching (TS) architecture at the relay, the data transmission is accomplished in three phases: Phase I) Energy harvesting by the untrusted relay and the FJ through non-information transmissions from the sources, Phase II) Information transmission by the sources and jamming transmissions from the FJ to reduce information leakage to the untrusted relay; and Phase III) Forwarding the scaled version of the received signal from the untrusted relay to the sources. For the proposed system, we derive a new closed-form lower bound expression for the ergodic secrecy sum rate (ESSR). Numerical examples are provided to demonstrate the impacts of different system parameters such as energy harvesting time, transmit signal-to-noise ratio (SNR) and the relay/FJ location on the secrecy performance. The numerical results illustrate that the proposed network with friendly jamming (WFJ) outperforms traditional one-way communication and the two-way without friendly jamming (WoFJ) policy.