Secrecy analysis of short-packet transmissions in ultra-reliable and low-latency communications

Jianhua He,Lei Yang,Guangheng Zhao,Xue Sun,Lu Wang

doi:10.1186/s13638-020-01862-7

Abstract

In this paper, we investigate the secrecy performance of short-packet transmissions in ultra-reliable and low-latency communications (URLLC). We consider the scenario where a multi-antenna source communicates with a single-antenna legitimate receiver requiring ultra-high reliability and low latency, in the presence of a single-antenna eavesdropper. In order to safeguard URLLC, the source transmits the artificial noise (AN) signal together with the confidential signal to confuse the eavesdropper. We adopt a lower bound on the maximal secrecy rate as the secrecy performance metric for short-packet transmissions in URLLC, which takes the target decoding error probabilities at the legitimate receiver and the eavesdropper into account. Using this metric, we first derive a compact expression of the generalized secrecy outage probability (SOP). Then, we formally prove that the generalized SOP is a convex function with respect to the power allocation factor between the confidential signal and the AN signal. We further determine the optimal power allocation factor that minimizes the generalized SOP. The results presented in this work can be useful for designing new secure transmission schemes for URLLC.

Highlights

Supporting ultra-reliable and low-latency communications (URLLC) is one of the major goals in the fifth generation (5G) and future wireless networks [1, 2], due to the requirements of various emerging applications, such as smart city, mission-critical internetof-things, and vehicle-to-vehicle communications [3, 4]
It follows that the classical information-theoretic secrecy is not achievable, and thereby the secrecy performance metrics commonly adopted in the existing physical layer security schemes cannot be utilized to characterize the secrecy performance of URLLC
4 Results and discussion Due to short-packet transmissions in URLLC, the confidential information is inevitably leaked to the eavesdropper and perfect secrecy cannot be achieved

Summary

Introduction

Supporting ultra-reliable and low-latency communications (URLLC) is one of the major goals in the fifth generation (5G) and future wireless networks [1, 2], due to the requirements of various emerging applications, such as smart city, mission-critical internetof-things, and vehicle-to-vehicle communications [3, 4]. The existing physical layer security schemes are commonly designed based on the classical information-theoretic secrecy, the key assumption of which is that the transmissions can be error-free and the information leaked to the eavesdropper vanishes as the blocklength of channel codes goes to infinity This assumption enables the use of secrecy performance metrics, such as the achievable secrecy rate and the secrecy outage probability (SOP), to characterize the secrecy performance of wireless communication systems. In URLLC, the blocklength of channel codes is short, which means the transmissions are no longer error-free and the information leaked to the eavesdropper cannot be vanished It follows that the classical information-theoretic secrecy is not achievable, and thereby the secrecy performance metrics commonly adopted in the existing physical layer security schemes cannot be utilized to characterize the secrecy performance of URLLC. We consider that the source transmits the artificial noise (AN) signal together with the confidential signal, and show how the secrecy performance of URLLC can be enhanced by judiciously selecting the power allocation factor between the confidential signal and the AN signal

Methods

Experiment

Results and discussion