Secure Communication with a Wireless-Powered Friendly Jammer

TL;DR

This paper introduces a protocol using a wireless-powered friendly jammer to secure communication against eavesdroppers, analyzing and optimizing throughput with different jammer antenna configurations.

Contribution

It provides a novel two-phase protocol with analytical throughput characterization and optimization for secure wireless communication using energy-harvesting jammers.

Findings

Throughput saturates with single-antenna jammer at high power

Multi-antenna jammer achieves unbounded throughput growth

Analytical results are validated by numerical simulations

Abstract

In this paper, we propose to use a wireless-powered friendly jammer to enable secure communication between a source node and destination node, in the presence of an eavesdropper. We consider a two-phase communication protocol with fixed-rate transmission. In the first phase, wireless power transfer is conducted from the source to the jammer. In the second phase, the source transmits the information-bearing signal under the protection of a jamming signal sent by the jammer using the harvested energy in the first phase. We analytically characterize the long-time behavior of the proposed protocol and derive a closed-form expression for the throughput. We further optimize the rate parameters for maximizing the throughput subject to a secrecy outage probability constraint. Our analytical results show that the throughput performance differs significantly between the single-antenna jammer case and the multi-antenna jammer case. For instance, as the source transmit power increases, the throughput quickly reaches an upper bound with single-antenna jammer, while the throughput grows unbounded with multi-antenna jammer. Our numerical results also validate the derived analytical results.