In this letter, we focus on the secrecy outage analysis of ultra-reliable low-latency communication (URLLC) systems in the presence of randomly located eavesdroppers and imperfect channel state information (CSI). To be specific, the secrecy outage probability (SOP) of pilot-assisted URLLC system is investigated, which is defined as the probability that either the reliability const-raint or the secrecy constraint cannot be satisfied when the packet is delivered with a target data rate and blocklength. In fact, the definition of SOP in URLLC scenarios with short-packet feature is evidently different from that in the infinite blocklength regime. Inspired by this, we first propose a novel analytical framework to approximate the SOP in a tractable manner. Then, the asymptotic behaviours of SOP in the high-SNR and large-antenna cases are also analyzed to gain a comprehensive insight. Numerical results illustrate how the SOP of our pilot-assisted URLLC system varies with specific transmission parameters.
In this letter, we focus on the secrecy outage analysis of ultra-reliable low-latency communication (URLLC) systems in the presence of randomly located eavesdroppers and imperfect channel state information (CSI). To be specific, the secrecy outage probability (SOP) of pilot-assisted URLLC system is investigated, which is defined as the probability that either the reliability const-raint or the secrecy constraint cannot be satisfied when the packet is delivered with a target data rate and blocklength. In fact, the definition of SOP in URLLC scenarios with short-packet feature is evidently different from that in the infinite blocklength regime. Inspired by this, we first propose a novel analytical framework to approximate the SOP in a tractable manner. Then, the asymptotic behaviours of SOP in the high-SNR and large-antenna cases are also analyzed to gain a comprehensive insight. Numerical results illustrate how the SOP of our pilot-assisted URLLC system varies with specific transmission parameters.
In this article, we focus on the pilot-assisted transmission design for secure ultra-reliable and low-latency communication (URLLC) systems, which has not yet been studied in the existing literatures. In each transmission period of this system, the multi-antenna controller sends confidential URLLC messages integrated with artificial noise (AN) to a single-antenna actuator for some mission-critical operations (e.g., remote control), and while an unknown number of passive eavesdroppers attempt to intercept this confidential message in a non-colluding manner. Since the conventional ergodic secrecy capacity is not accurate to describe the maximal achievable secrecy rate of URLLC with short blocklength coding, we establish the concept of achievable effective secrecy rate (AESR) to measure the secrecy performance of our URLLC system, which is defined as the average number of information bits can be transmitted per channel use under given reliability and information leakage constraints. Due to the exact expression of AESR has an intractable form, we derive a closed-form approximation on the AESR to simplify the calculation, via leveraging the Laplace approximation and Gaussian-Chebyshev quadrature method. Following by this approximation, we propose an efficient two-dimensional search algorithm to determine the optimal transmission parameters that maximize the AESR, i.e., the training pilot length and the power allocation ratio between confidential data signals and AN. Furthermore, the asymptotic performance of AESR in the high-SNR regime is also analyzed to gain more insights. Numerical results validate the accuracy of theoretical approximations presented in this paper, and illustrate how the particular system parameters impact the AESR of our considered URLLC system.
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.
This paper for the first time investigate the security and reliability performance of ultra-reliable low-latency communication (URLLC) systems in the presence of randomly distributed eavesdroppers, where the impact of short blocklength codes and imperfect channel estimation are jointly considered. Based on the finite-blocklength information theory, we first derive a closed-form approximation of transmission error probability to describe the degree of reliability loss. Then, we also derive an asymptotic expression of intercept probability to characterize the security performance, where the impact of secrecy protected zone is also considered. Simulation and numerical results validate the accuracy of theoretical approximations, and illustrate the tradeoff between security and reliability. That is, the intercept probability of URLLC systems can be suppressed by loosening the reliability requirement, and vice versa. More importantly, the theoretical analysis and methodologies presented in this paper can offer some insights and design guidelines for supporting secure URLLC applications in the future 6G wireless networks.
In this article, we focus on the joint design of channel training and data transmission for secure ultrareliable and low-latency communications (URLLCs) in mission-critical Internet of Things (IoT) scenarios, e.g., intelligent transportation and remote control. Specifically, we consider a multiple-input multiple-output multiantenna eavesdropper (MIMOME) system, and the role of artificial noise (AN) for securing URLLC in this system is studied. In the channel training phase, we use the two-way discriminatory channel estimation (DCE) protocol with AN injection to suppress the channel estimation accuracy at eavesdropper. Meanwhile, the AN-assisted secrecy beamforming scheme is adopted to mask the confidential data signals. Following by the security enhancements above, we provide a quantitative definition of achievable effective secrecy rate (AESR) to measure the performance of our URLLC system with imperfect channel state information (CSI) and short-packet feature. Then, a nonasymptotic closed-form lower bound of AESR is provided to make the numerical calculation tractable, and the asymptotic system performance in the high-SNR regime is also studied to gain a comprehensive insight. Based on the cyclic coordinated search method, we propose an iterative resource allocation algorithm to maximize the AESR of our system, where the blocklength and transmit power assigned to the reverse/forward pilots, confidential data signals, and AN are jointly optimized. In addition, numerical results reveal the AESR performance of our URLLC system for different system parameters, and demonstrate the convergence and superiority of our proposed algorithm.
This paper presents a secure downlink communication system where a transmitter with multiple antennas sends information to multiple single antenna users under ultra reliable and low-latency communication (uRLLC) system requirement. To meet uRLLC requirement and provide secrecy against multi-antenna eavesdropper (Eve), transmitter adopts a special channel training scheme called anti-eavesdropping channel estimation (ANECE) as well as a standard transmit beamforming to send secret information in short blocklength regime. Using ANECE, two or more cooperative full-duplex radio devices obtain their receive channel state information (CSI) with respect to each other while preventing Eve from obtaining a consistent estimate of its receive CSI, which improves the secrecy of subsequent transmission of information between the devices. We derive an expression for the average secrecy throughput (AST) of ANECE assisted transmission. This easy-to-evaluate expression of approximated AST in terms of blocklength and various controllable parameters leads to useful insights to maximize AST under uRLLC requirement. Finally, numerical results are presented and discussed.
We analyze the secrecy outage performance of a mixed radio frequency-free space optical (RF-FSO) transmission system with imperfect channel state information (CSI). We deal with a single-input multiple-output wiretap model, where a base station (works as the relay) forwards the signal transmitted from a user (source) to a data center (works as the destination), while an eavesdropper wiretaps the confidential information by decoding the received signal. Both the relay and the eavesdropper are armed with multiple antennas, and maximal ratio combining scheme is utilized to improve the received signal-to-noise ratio (SNR). The effects of imperfect CSI of the RF link and the FSO link, misalignment, detection schemes, and relaying schemes on the secrecy outage performance of mixed RF-FSO systems are studied. First, the cumulative distribution function and probability density function of FSO links with pointing error and two different detection technologies are derived. Then, we derive the closed-form expressions for the lower bound of the secrecy outage probability (SOP) with fixed-gain relaying and variable-gain relaying schemes. Furthermore, asymptotic results for the SOP are investigated by exploiting the unfolding of Meijer's G-function when the electrical SNR of FSO link approaches infinity. Finally, Monte Carlo simulation results are presented to corroborate the correctness of the analysis.