Shotgun cellular systems (SCSs) are stochastic models of wireless networks where base stations (BSs) are randomly deployed across spatial settings of dimension one, two, or three, under a Poisson point process (PPP). As the physical layer security (PLS) of SCSs depends on BS density—which is influenced by the network’s setup and deployment—and typically underperforms compared to ideal hexagonal cellular systems (HCSs), this paper proposes an enhancement of PLS—including average secrecy capacity (ASC), secrecy outage probability (SOP), and the probability of non-zero secrecy capacity (PNZSC)—by leveraging side information (SI) available at the transmitter in addition to the source message for Wyner’s three-node model under realistic conditions, where shadowing coefficients of the channels are arbitrarily correlated. Modeling the shadowing on both the main (transmitter–legitimate receiver) and eavesdropper (transmitter–eavesdropper) channels with a lognormal (LN) distribution—the standard and most accurate model for characterizing shadowing—yields closed-form expressions for the aforementioned PLS performance metrics, thereby providing rigorous analytical insights. Lastly, the correctness of the analytical findings is confirmed via Monte Carlo (MC) simulation experiments.
Shotgun cellular systems (SCSs) are stochastic models of wireless networks where base stations (BSs) are randomly deployed across spatial settings of dimension one, two, or three, under a Poisson point process (PPP). As the physical layer security (PLS) of SCSs depends on BS density—which is influenced by the network’s setup and deployment—and typically underperforms compared to ideal hexagonal cellular systems (HCSs), this paper proposes an enhancement of PLS—including average secrecy capacity (ASC), secrecy outage probability (SOP), and the probability of non-zero secrecy capacity (PNZSC)—by leveraging side information (SI) available at the transmitter in addition to the source message for Wyner’s three-node model under realistic conditions, where shadowing coefficients of the channels are arbitrarily correlated. Modeling the shadowing on both the main (transmitter–legitimate receiver) and eavesdropper (transmitter–eavesdropper) channels with a lognormal (LN) distribution—the standard and most accurate model for characterizing shadowing—yields closed-form expressions for the aforementioned PLS performance metrics, thereby providing rigorous analytical insights. Lastly, the correctness of the analytical findings is confirmed via Monte Carlo (MC) simulation experiments.
In this paper, under correlated shadowing channels-a propagation model that accurately reflects real-world wireless environment-we consider a multi-eavesdropper wiretap channel, in which several passive eavesdroppers independently try to intercept the legitimate transmission over the primary communication path from the transmitter (Tx) to the authorized receiver (Rx), constituting a realistic threat model, and analyze the achievable physical layer security (PLS) of wireless system, where, motivated by the proven positive impact of side information (SI) at the Tx on PLS performance, SI is assumed to be available at the Tx. Unlike previous studies that either considered (i) a single eavesdropper under correlated fading channels, with SI present or absent, or (ii) multiple eavesdroppers under independent fading channels, in the absence of SI, this work jointly incorporates SI at the Tx and multiple eavesdroppers under correlated shadowing conditions, yielding a more realistic and effective system model for secure wireless communication. There is no intercorrelation among the eavesdroppers, and the probability of information leakage is zero if none of them can successfully eavesdrop on the transmission. The shadowing experienced over the Tx–authorized Rx channel and the eavesdropper channels (the link between the Tx and each eavesdropper) is modeled using a Log-normal (LN) probability model, which is widely used in communication platforms that rely on wireless transmission to characterize shadowing caused by obstacles and environmental inhomogeneities, based on which we derive fast and accurate approximate closed-form expressions using the Holtzman method (HM) for the average secrecy capacity (ASC), secrecy outage probability (SOP), and the probability of non-zero secrecy capacity (PNSC).The resulting analytical expressions are mathematically tractable, and their validity is confirmed by benchmarking them against Monte Carlo (MC) simulations, and they offer reduced computational complexity and faster execution compared to simulation-based outcomes.
In this paper, we analyze the performance of physical layer security (PLS) in Weibull fading wiretap channels (WTC), leveraging realistic channel propagation models in which the channel coefficients of the main (transmitter-to-legitimate receiver) and eavesdropper (transmitter-to-eavesdropper) channels are correlated. Additionally, by incorporating non-causally known side information (SI) at the transmitter, we enhance PLS in this context. We utilize the Farlie–Gumbel–Morgenstern (FGM) copula to model the correlation between the main and eavesdropper channels, enabling us to derive analytical expressions for the average secrecy capacity (ASC), secrecy outage probability (SOP), the lower bound of SOP (LSOP), and the strictly positive secrecy capacity (SPSC) across various dependence scenarios (i.e., negative, positive, and independent). The numerically evaluated results, validated through corresponding computer simulations, provide valuable insights into the impact of channel correlation and SI at the transmitter on the system’s PLS performance.
In this paper, we investigate the impact of side information (SI) on the performance of physical layer security (PLS) under correlated fading channels. By considering non-causally known SI at the transmitter and exploiting the copula technique to describe the fading correlation, we derive closed-from expressions for the average secrecy capacity (ASC) and secrecy outage probability (SOP) under positive/negative dependence conditions. We indicate that considering such knowledge at the transmitter is beneficial for system performance and ensures reliable communication with higher rates, as it improves the SOP and brings higher values of the ASC.
The performance of physical-layer security of the classic Wyner's wiretap model over Fisher-Snedecor F composite fading channels is considered in this work. Specifically, the main channel (i.e., between the source and the legitimate destination) and the eavesdropper's channel (i.e., between the source and the illegitimate destination) are assumed to experience independent quasi-static Fisher-Snedecor F fading conditions, which have been shown to be encountered in realistic wireless transmission scenarios in conventional and emerging communication systems. In this context, exact closed-form expressions for the average secrecy capacity (ASC) and the probability of non-zero secrecy capacity (PNSC) are derived. Additionally, an asymptotic analytical expression for the ASC is presented. The impact of shadowing and multipath fading on the secrecy performance is investigated. Our results show that increasing the fading parameter of the main channel and/or the shadowing parameter of the eavesdropper's channel improves the secrecy performance. The analytical results are compared with Monte-Carlo simulations to validate the analysis.
This paper investigates the performance of physical layer security (PLS) in fluid antenna-aided communication systems under arbitrary correlated fading channels. In particular, it is considered that a single fixed-antenna transmitter aims to send confidential information to a legitimate receiver equipped with a planar fluid antenna system (FAS), while an eavesdropper, also taking advantage of a planar FAS, attempts to decode the desired message. For this scenario, we first present analytical expressions of the equivalent channel distributions at the legitimate user and eavesdropper by using copula, so that the obtained analytical results are valid for any arbitrarily correlated fading distributions. Then, with the help of Gauss-Laguerre quadrature, we derive compact analytical expressions for the average secrecy capacity (ASC), the secrecy outage probability (SOP), and the secrecy energy efficiency (SEE) for the FAS wiretap channel. Moreover, for exemplary purposes, we also obtain the compact expression of ASC, SOP, and SEE by utilizing the Gaussian copula under correlated Rayleigh fading channels as a special case. Eventually, numerical results indicate that applying the fluid antenna with only one activated port to PLS can guarantee more secure and reliable transmission, when compared to traditional antenna systems (TAS) exploiting maximal ratio combining (MRC) and antenna selection (AS) under selection combining (SC).
We investigate the physical layer security limits of Wyner's wiretap model over Fisher-Snedecor .T composite fading channels. .T fading conditions have been recently shown to provide an accurate characterization of multipath fading and shadowing effects in emerging wireless transmission scenarios such as body centric, cellular and vehicular communications. To this end, we utilize a redefined analytic expression for the Fisher-Snedecor .T distribution in order to ensure unconstrained validity and reliability when used in the analysis of various performance metrics of interest. In this context, we assume that the main channel (i.e., between the source and the legitimate destination) and the eavesdropper's channel (i.e., between the source and the illegitimate destination) undergo independent quasi-static Fisher-Snedecor .T composite fading. Novel exact analytic expressions are then derived for the corresponding average secrecy capacity (ASC), secure outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC) along with their insightful asymptotic representations. In addition, analytical expressions for the ASC, SOP and SPSC over mixed fading channels such as Nakagami-m/Nakagami-m, Nakagami-m/Fisher-Snedecor .T and Fisher-Snedecor .T/Nakagami-m are derived. The new formulations are validated through comparisons with Monte-Carlo simulations and analyzed to gain useful insights into the impact of the fading parameters on the achievable accuracy and the overall system performance.