Secrecy Outage Probability Analysis of Multi-User Multi-Eavesdropper Wireless Systems

TL;DR

This paper analyzes the secrecy outage probability in multi-user, multi-eavesdropper wireless systems, proposing a new multi-user scheduling scheme that enhances security without needing eavesdropper CSI, outperforming traditional round-robin scheduling.

Contribution

It introduces a multi-user scheduling method requiring only BS channel information, with derived closed-form secrecy outage expressions and demonstrated improved security performance.

Findings

Multi-user scheduling reduces secrecy outage probability as user number increases.

Proposed scheme outperforms round-robin scheduling in security metrics.

Secrecy outage remains unchanged for round-robin with more users.

Abstract

In this paper, we explore the physical-layer security of a multi-user wireless system that consists of multiple users intending to transmit to a base station (BS), while multiple eavesdroppers attempt to tap the user transmissions. We examine the employment of multi-user scheduling for improving the transmission security against eavesdropping and propose a multi-user scheduling scheme, which only requires the channel state information (CSI) of BS without the need of the passive eavesdroppers' CSI. We also consider the round-robin scheduling for comparison purposes. The closed-form secrecy outage probability expressions of the round-robin scheduling and proposed multi-user scheduling are derived over Rayleigh fading channels. Numerical results demonstrate that the proposed multi-user scheduling outperforms the round-robin scheduling in terms of the secrecy outage probability. As the number of users increases, the secrecy outage probability of round-robin scheduling keeps unchanged. By contrast, the secrecy outage performance of the proposed multi-user scheduling improves significantly with an increasing number of users.