Secure Analog Network Coding in Layered Networks

TL;DR

This paper analyzes the maximum achievable secrecy rate in layered Gaussian relay networks using analog network coding, providing optimal scaling strategies and demonstrating near-capacity performance in high-SNR conditions.

Contribution

It introduces a lemma for globally optimal scaling factors that maximize secrecy rate and characterizes secure ANC performance in multi-layered networks with an eavesdropper.

Findings

Optimal scaling factors for maximum secrecy rate derived

ANC achieves near-capacity secrecy rates at high SNR

First characterization of secure ANC in layered networks with eavesdroppers

Abstract

We consider a class of Gaussian layered networks where a source communicates with a destination through $L$ intermediate relay layers with $N$ nodes in each layer in the presence of a single eavesdropper which can overhear the transmissions of the nodes in any one layer. The problem of maximum secrecy rate achievable with analog network coding for a unicast communication over such layered wireless relay networks with directed links is considered. A relay node performing analog network coding scales and forwards the signals received at its input. The key contribution of this work is a lemma that provides the globally optimal set of scaling factors for the nodes that maximizes the end-to-end secrecy rate for a class of layered networks. We also show that in the high-SNR regime, ANC achieves secrecy rates within a constant gap of the cutset upper bound on the secrecy capacity. To the best of our knowledge, this work offers the first characterization of the performance of secure ANC in multi-layered networks in the presence of an eavesdropper.