Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Performance Analysis of Finite Blocklength Transmissions Over Wiretap Fading Channels: An Average Information Leakage Perspective

Milad Tatar Mamaghani, Xiangyun Zhou, Nan Yang, A. Lee Swindlehurst, H. Vincent Poor

TL;DR

This work addresses secrecy in finite-blocklength transmissions over fading wiretap channels with unknown Eve CSI by introducing Average Information Leakage (AIL) and linking it to the conventional secrecy outage probability (SOP). It develops a general framework to evaluate exact and approximate AIL under arbitrary fading and precoding, and provides closed-form AIL expressions for Rayleigh and Rician fading with artificial-noise beamforming. Through case studies, it shows that a small allowance in information leakage can substantially improve reliability, and demonstrates how blocklength design and AN power allocation impact average secrecy throughput (AST). The paper also presents adaptive and non-adaptive transmission designs to maximize AST under reliability and secrecy constraints, offering practical guidance for secure beyond-5G FBL communications. Overall, the results show that AN beamforming coupled with judicious blocklength and power allocation can drive AIL toward zero at high SNR, while maintaining reliable communication, thereby enhancing the security-performance trade-offs in fading wireless networks.

Abstract

Physical-layer security (PLS) is a promising technique to complement more traditional means of communication security in beyond-5G wireless networks. However, studies of PLS are often based on ideal assumptions such as infinite coding blocklengths or perfect knowledge of the wiretap link's channel state information (CSI). In this work, we study the performance of finite blocklength (FBL) transmissions using a new secrecy metric $\unicode{x2013}$ the average information leakage (AIL). We evaluate the exact and approximate AIL with Gaussian signaling and arbitrary fading channels, assuming that the eavesdropper's instantaneous CSI is unknown. We then conduct case studies that use artificial noise (AN) beamforming to analyze the AIL in both Rayleigh and Rician fading channels. The accuracy of the analytical expressions is verified through extensive simulations, and various insights regarding the impact of key system parameters on the AIL are obtained. Particularly, our results reveal that allowing a small level of AIL can potentially lead to significant reliability enhancements. To improve the system performance, we formulate and solve an average secrecy throughput (AST) optimization problem via both non-adaptive and adaptive design strategies. Our findings highlight the significance of blocklength design and AN power allocation, as well as the impact of their trade-off on the AST.

Performance Analysis of Finite Blocklength Transmissions Over Wiretap Fading Channels: An Average Information Leakage Perspective

TL;DR

This work addresses secrecy in finite-blocklength transmissions over fading wiretap channels with unknown Eve CSI by introducing Average Information Leakage (AIL) and linking it to the conventional secrecy outage probability (SOP). It develops a general framework to evaluate exact and approximate AIL under arbitrary fading and precoding, and provides closed-form AIL expressions for Rayleigh and Rician fading with artificial-noise beamforming. Through case studies, it shows that a small allowance in information leakage can substantially improve reliability, and demonstrates how blocklength design and AN power allocation impact average secrecy throughput (AST). The paper also presents adaptive and non-adaptive transmission designs to maximize AST under reliability and secrecy constraints, offering practical guidance for secure beyond-5G FBL communications. Overall, the results show that AN beamforming coupled with judicious blocklength and power allocation can drive AIL toward zero at high SNR, while maintaining reliable communication, thereby enhancing the security-performance trade-offs in fading wireless networks.

Abstract

Physical-layer security (PLS) is a promising technique to complement more traditional means of communication security in beyond-5G wireless networks. However, studies of PLS are often based on ideal assumptions such as infinite coding blocklengths or perfect knowledge of the wiretap link's channel state information (CSI). In this work, we study the performance of finite blocklength (FBL) transmissions using a new secrecy metric the average information leakage (AIL). We evaluate the exact and approximate AIL with Gaussian signaling and arbitrary fading channels, assuming that the eavesdropper's instantaneous CSI is unknown. We then conduct case studies that use artificial noise (AN) beamforming to analyze the AIL in both Rayleigh and Rician fading channels. The accuracy of the analytical expressions is verified through extensive simulations, and various insights regarding the impact of key system parameters on the AIL are obtained. Particularly, our results reveal that allowing a small level of AIL can potentially lead to significant reliability enhancements. To improve the system performance, we formulate and solve an average secrecy throughput (AST) optimization problem via both non-adaptive and adaptive design strategies. Our findings highlight the significance of blocklength design and AN power allocation, as well as the impact of their trade-off on the AST.
Paper Structure (27 sections, 4 theorems, 70 equations, 9 figures)

This paper contains 27 sections, 4 theorems, 70 equations, 9 figures.

Table of Contents

  1. Introduction
  2. Related Works and Motivation
  3. Contributions
  4. Organization and Notation
  5. System Model
  6. Secure FBL communication
  7. Secrecy Performance
  8. Average Information Leakage
  9. Secrecy Outage vs. Average Information Leakage
  10. Performance Analysis: Case Studies
  11. Rayleigh Fading
  12. (Case I)
  13. (Case II)
  14. Rician Fading
  15. (Case I)
  16. ...and 12 more sections

Key Result

Proposition 1

The average information leakage (AIL) $\bar{\delta}$ for the considered wiretap channel can be approximately calculated as where $F_{\gamma_e}(\cdot)$ is the CDF of $\gamma_e$, and $x_0$ is defined for $x_0\geq 0$ as

Figures (9)

  • Figure 1: System model for typical wiretap FBL communication in IoT networks.
  • Figure 2: Comparison between $F_{\gamma_e}(x)$, labeled as Sim. and $F_Z(x)$, marked as Approx. for different transmit SNRs. The simulation parameters are set as $\alpha = 0.7$, $\beta_b = 3$, $\beta_e = 1$, $K_b=K_e=5$, and $k=4$.
  • Figure 3: AIL vs. transmit SNR for different fading channels and beamforming schemes.
  • Figure 4: AIL vs. blocklength for Rician fading with AN beamforming ($\alpha = 0.7$) for different K-factors and numbers of Alice's antennas.
  • Figure 5: AIL vs. decoding error probability for Rayleigh fading.
  • ...and 4 more figures

Theorems & Definitions (10)

  • Remark 1
  • Proposition 1
  • proof
  • Remark 2
  • Corollary 1
  • Remark 3
  • Lemma 1
  • proof
  • Lemma 2
  • Remark 4