On Secure Transmission over Parallel Relay Eavesdropper Channel

TL;DR

This paper analyzes secure communication over a parallel relay-eavesdropper channel, establishing bounds on secrecy rates and proposing relay strategies for optimal secure transmission in both discrete and Gaussian models.

Contribution

It introduces new bounds on the rate-equivocation region for the parallel relay-eavesdropper channel and explores relay mode selection for enhanced security.

Findings

Inner and outer bounds on rate-equivocation region established

Bounds on perfect secrecy rate for Gaussian model derived

Relay mode selection impacts secure transmission effectiveness

Abstract

We study a four terminal parallel relay-eavesdropper channel which consists of multiple independent relay-eavesdropper channels as subchannels. For the discrete memoryless case, we establish inner and outer bounds on the rate-equivocation region. For each subchannel, secure transmission is obtained through one of the two coding schemes at the relay: decoding-and-forwarding the source message or confusing the eavesdropper through noise injection. The inner bound allows relay mode selection. For the Gaussian model we establish lower and upper bounds on the perfect secrecy rate. We show that the bounds meet in some special cases, including when the relay does not hear the source. We illustrate the analytical results through some numerical examples.