Full-Duplex vs. Half-Duplex Secret-Key Generation

TL;DR

This paper investigates how full-duplex communication can enhance secret-key generation in wireless systems, showing that FD can outperform half-duplex under certain conditions even without perfect self-interference cancellation.

Contribution

It introduces two models for FD and HD secret-key generation, compares their performance, and analyzes the impact of various factors including eavesdropper strength and SNR regimes.

Findings

FD can improve secret-key rates over HD in specific scenarios.

Perfect self-interference cancellation is not required for FD advantages.

FD mode can hinder eavesdropper capabilities under certain conditions.

Abstract

Full-duplex (FD) communication is regarded as a key technology in future 5G and Internet of Things (IoT) systems. In addition to high data rate constraints, the success of these systems depends on the ability to allow for confidentiality and security. Secret-key agreement from reciprocal wireless channels can be regarded as a valuable supplement for security at the physical layer. In this work, we study the role of FD communication in conjunction with secret-key agreement. We first introduce two complementary key generation models for FD and half-duplex (HD) settings and compare the performance by introducing the key-reconciliation function. Furthermore, we study the impact of the so called probing-reconciliation trade-off, the role of a strong eavesdropper and analyze the system in the high SNR regime. We show that under certain conditions, the FD mode enforces a deteriorating impact on the capabilities of the eavesdropper and offers several advantages in terms of secret-key rate over the conventional HD setups. Our analysis reveals as an interesting insight that perfect self-interference cancellation is not necessary in order to obtain performance gains over the HD mode.