On Secure Communication using RF Energy Harvesting Two-Way Untrusted Relay

TL;DR

This paper investigates secure wireless communication via RF energy harvesting in a two-way relay system with an untrusted relay, proposing optimal power allocation and jamming strategies to maximize secrecy rates despite channel uncertainties.

Contribution

It introduces an optimal power allocation and jamming scheme for secure RF energy harvesting two-way relay communication with untrusted relays, considering imperfect channel information.

Findings

Jammer effectively enhances secrecy under channel estimation errors.

Optimal power allocation reduces jammer power as channel estimation errors increase.

Numerical results confirm the importance of jamming in secure energy harvesting communications.

Abstract

We focus on a scenario where two wireless source nodes wish to exchange confidential information via an RF energy harvesting untrusted two-way relay. Despite its cooperation in forwarding the information, the relay is considered untrusted out of the concern that it might attempt to decode the confidential information that is being relayed. To discourage the eavesdropping intention of the relay, we use a friendly jammer. Under the total power constraint, to maximize the sum-secrecy rate, we allocate the power among the sources and the jammer optimally and calculate the optimal power splitting ratio to balance between the energy harvesting and the information processing at the relay. We further examine the effect of imperfect channel state information at both sources on the sum-secrecy rate. Numerical results highlight the role of the jammer in achieving the secure communication under channel estimation errors. We have shown that, as the channel estimation error on any of the channels increases, the power allocated to the jammer decreases to abate the interference caused to the confidential information reception due to the imperfect cancellation of jammer's signal.