Secure Multi-Hop Relaying in Large-Scale Space-Air-Ground-Sea Integrated Networks

TL;DR

This paper presents a joint optimization framework for secure multi-hop relaying in large-scale space-air-ground-sea networks, enhancing security and throughput in 6G wireless systems.

Contribution

It introduces a novel cross-layer optimization method that maximizes user throughput while ensuring secure connections, including a closed-form SPSC probability and an efficient relay routing algorithm.

Findings

Achieves near-optimal relay routing performance.

Provides a closed-form expression for secure connection probability.

Validates framework effectiveness on real-world datasets.

Abstract

As a key enabler of borderless and ubiquitous connectivity, space-air-ground-sea integrated networks (SAGSINs) are expected to be a cornerstone of 6G wireless communications. However, the multi-tiered and global-scale nature of SAGSINs also amplifies the security vulnerabilities, particularly due to the hidden, passive eavesdroppers distributed throughout the network. In this paper, we introduce a joint optimization framework for multi-hop relaying in SAGSINs that maximizes the minimum user throughput while ensuring a minimum strictly positive secure connection (SPSC) probability. We first derive a closed-form expression for the SPSC probability and incorporate this into a cross-layer optimization framework that jointly optimizes radio resources and relay routes. Specifically, we propose an $\mathcal{O}(1)$ optimal frequency allocation and power splitting strategy-dividing power levels of data transmission and cooperative jamming. We then introduce a Monte-Carlo relay routing algorithm that closely approaches the performance of the numerical upper-bound method. We validate our framework on testbeds built with real-world dataset.