We present a general and compact framework for the analysis of the wireless information-theoretic security of arbitrarily-distributed fading channels. We show that performance metrics such as the outage probability of the secrecy capacity, the probability of strictly positive secrecy capacity and the e-outage secrecy capacity can be compactly expressed in terms of the moment generating function (MGF) of the fading models. Using this approach, we can study the effect of considering different propagation conditions for the legitimate and eavesdropper's fading links, which accommodate to many practical scenarios.
We present a general and compact framework for the analysis of the wireless information-theoretic security of arbitrarily-distributed fading channels. We show that performance metrics such as the outage probability of the secrecy capacity, the probability of strictly positive secrecy capacity and the e-outage secrecy capacity can be compactly expressed in terms of the moment generating function (MGF) of the fading models. Using this approach, we can study the effect of considering different propagation conditions for the legitimate and eavesdropper's fading links, which accommodate to many practical scenarios.
This paper proposes a novel method to provide secrecy outage performance in various fading environments using a mixture gamma (MG) distribution, which is well known to approximate numerous fading channel models. First, we derive the generalized moment generating function (G-MGF) and incomplete G-MGF (IG-MGF) of the MG distribution. Then, by applying those formulas, we obtain the exact and asymptotic expressions of the secrecy outage probability along with the corresponding lower bound and probability of the strictly positive secrecy capacity for various fading scenarios. Finally, the accuracy and effectiveness of all derived formulas are verified through extensive numerical experiments.
Abstract Physical layer security is a feasible solution to improve wireless communication secrecy against eavesdropping threats. Within this framework, this work examines the secrecy performance of a wireless link subjected to eavesdropping over generalized composite fading environments, specifically using the α-η-µ/Lognormal and α-κ-µ/Lognormal distributions. Closed-form results are derived for key secrecy performance metrics, including the average secrecy capacity (ASC), a lower bound on the secrecy outage probability SOPL, and the probability of strictly positive secrecy capacity (SPSC). Additionally, asymptotic analyses of ASC, SOPL, and SPSC are presented in the high-SNR regime to yield simplified insights into system behavior. The analysis accommodates arbitrary and independent fading conditions for the main and eavesdropper channels, thereby enabling a comprehensive evaluation of the impact of various channel parameters. Ultimately, all analytical outcomes are corroborated using comprehensive Monte Carlo simulations, affirming their precision and relevance.
Theoretical studies on physical layer security often adopt the secrecy outage probability as the performance metric for wireless communications over quasi-static fading channels. The secrecy outage probability has two limitations from a practical point of view: 1) it does not give any insight into the eavesdropper's decodability of confidential messages and 2) it cannot characterize the amount of information leakage to the eavesdropper when an outage occurs. Motivated by the limitations of the secrecy outage probability, we propose three new secrecy metrics for secure transmissions over quasi-static fading channels. The first metric establishes a link between the concept of secrecy outage and the decodability of messages at the eavesdropper. The second metric provides an error-probability-based secrecy metric which is typically used for the practical implementation of secure wireless systems. The third metric characterizes how much or how fast the confidential information is leaked to the eavesdropper. We show that the proposed secrecy metrics collectively give a more comprehensive understanding of physical layer security over fading channels and enable one to appropriately design secure communication systems with different views on how secrecy is measured.
Theoretical studies on physical layer security often adopt the secrecy outage probability as the performance metric for wireless communications over quasi-static fading channels. The secrecy outage probability has two limitations from a practical point of view: 1) it does not give any insight into the eavesdropper's decodability of confidential messages and 2) it cannot characterize the amount of information leakage to the eavesdropper when an outage occurs. Motivated by the limitations of the secrecy outage probability, we propose three new secrecy metrics for secure transmissions over quasi-static fading channels. The first metric establishes a link between the concept of secrecy outage and the decodability of messages at the eavesdropper. The second metric provides an error-probability-based secrecy metric which is typically used for the practical implementation of secure wireless systems. The third metric characterizes how much or how fast the confidential information is leaked to the eavesdropper. We show that the proposed secrecy metrics collectively give a more comprehensive understanding of physical layer security over fading channels and enable one to appropriately design secure communication systems with different views on how secrecy is measured.
Nakagami-m fading channel is chosen to analyze the secrecy capacity for fading channels since the Nakagami-m distribution can model fading conditions, which are more or less severe than that of Rayleigh and has the advantage of including Rayleigh as a special case. At first, secrecy capacity is defined in case of full channel state information (CSI) at the transmitter, where transmitter has access to both the main channel and eavesdropper channel gains. Secondly, secrecy capacity is defined with only main channel CSI at the transmitter. Then, optimal power allocation at the transmitter that achieves the secrecy capacity is derived for both the cases. Moreover, secrecy capacity is defined under open-loop transmission scheme, and the exact closed form analytical expression for the lower bound of ergodic secrecy capacity is derived for Nakagami-m fading single-input multiple-output (SIMO) channel. In addition, secrecy capacity is defined for the AWGN channel in order to realize the information-theoretic security of wireless channels with no fading. Finally, analytical expressions for the probability of non-zero secrecy capacity and secure outage probability are derived in order to investigate the secure outage performance of fading channels.
In this paper, the physical layer security over the M-distributed fading channel is investigated. Initially, an exact expression of secrecy outage probability (SOP) is derived, which has an integral term. To get a closed-form expression, a lower bound of SOP is obtained. After that, the exact expression for the probability of strictly positive secrecy capacity (SPSC) is derived, which is in closed-form. Finally, an exact expression of ergodic secrecy capacity (ESC) is derived, which has two integral terms. To reduce its computational complexity, a closed-from expression for the lower bound of ESC is obtained. As special cases of M-distributed fading channels, the secure performance of the K, exponential, and Gamma-Gamma fading channels are also derived, respectively. Numerical results show that all theoretical results match well with Monte-Carlo simulation results. Specifically, when the average signal-to-noise ratio of main channel is larger than 40 dB, the relative errors for the lower bound of SOP, the probability of SPSC, and the lower bound of ESC are less than 1.936%, 6.753%, and 1.845%, respectively. This indicates that the derived theoretical expressions can be directly used to evaluate system performance without time-consuming simulations. Moreover, the derived results regarding parameters that influence the secrecy performance will enable system designers to quickly determine the optimal available parameter choices when facing different security risks.