On the Design of Secure Full-Duplex Multiuser Systems under User Grouping Method

TL;DR

This paper proposes a novel user grouping method and a low-complexity path-following algorithm to enhance physical layer security in full-duplex multiuser systems, effectively maximizing the minimum secrecy rate amidst eavesdroppers.

Contribution

It introduces a new user grouping technique combined with a convex optimization-based algorithm for secure full-duplex multiuser communication systems.

Findings

The proposed method outperforms conventional full-duplex systems.

The algorithm guarantees convergence to a local optimum.

Numerical results validate the effectiveness of the approach.

Abstract

Consider a full-duplex (FD) multiuser system where an FD base station (BS) is designed to simultaneously serve both downlink users and uplink users in the presence of half-duplex eavesdroppers (Eves). Our problem is to maximize the minimum secrecy rate (SR) among all legitimate users by proposing a novel user grouping method, where information signals at the FD-BS are accompanied with artificial noise to degrade the Eves' channel. The SR problem has a highly nonconcave and nonsmooth objective, subject to nonconvex constraints due to coupling between the optimization variables. Nevertheless, we develop a path-following low-complexity algorithm, which invokes only a simple convex program of moderate dimensions at each iteration. We show that our path-following algorithm guarantees convergence at least to a local optima. The numerical results demonstrate the merit of our proposed approach compared to existing well-known ones, i.e., conventional FD and nonorthogonal multiple access.