The wiretap channel model in a wireless scenario is analyzed where there is a transmitter, multiple legitimate receivers, non-colluding and colluding eavesdroppers; each of them is equipped with one antenna. Furthermore, all the channels are mutually independent and experiencing quasi-static Nakagami-m fading. We derive closed-form expressions for the exact secrecy outage probability as well as the average secrecy capacity with both non-colluding and colluding eavesdroppers. Such performance metrics are used to analyze the impacts of the number of receivers and eavesdroppers on the system. Remarkably, our results reveal that, for non-colluding eavesdroppers, increasing the number of users will cause greater secrecy degradation than the number of eavesdroppers, especially when the main channel is far superior to the wiretap channel or the value of the fading parameter is high. And for the colluding case, it turns out to be the opposite.
The wiretap channel model in a wireless scenario is analyzed where there is a transmitter, multiple legitimate receivers, non-colluding and colluding eavesdroppers; each of them is equipped with one antenna. Furthermore, all the channels are mutually independent and experiencing quasi-static Nakagami-m fading. We derive closed-form expressions for the exact secrecy outage probability as well as the average secrecy capacity with both non-colluding and colluding eavesdroppers. Such performance metrics are used to analyze the impacts of the number of receivers and eavesdroppers on the system. Remarkably, our results reveal that, for non-colluding eavesdroppers, increasing the number of users will cause greater secrecy degradation than the number of eavesdroppers, especially when the main channel is far superior to the wiretap channel or the value of the fading parameter is high. And for the colluding case, it turns out to be the opposite.
This paper studies the physical-layer security (PLS) of a system model consisting of a transmitter, a receiver, and multiple eavesdroppers. Cascaded general fading channel, which is the κ-μ distribution is assumed at the main and the wiretap links of the network. The impacts of the cascade level, the number of eavesdroppers attempting to overhear the confidential information, and the wiretap channel's parameters on the system's secrecy are investigated. Two of the main secrecy metrics are used to evaluate the secrecy level of the system, which are the secrecy outage probability (OPsec) and the probability of non-zero secrecy capacity (Pnsc). Exact and asymptotic form expressions for (OPsec) and (Pnsc) are derived. Asymptotic analysis is performed to gain a clear vision about the impact of some key parameters over the secrecy. The results show that the fading channel cascade level has a significant effect on the system's secrecy. Also, the results show that the system is less protected when increasing the number of eavesdroppers or when improving the wiretap channel's conditions. Analytical results are validated using Monte-Carlo simulations.
The impact of antenna correlation on secrecy performance in wireless communication networks is analyzed. This network consists of a signal antenna at the source, while receiver and eavesdropper are both equipped with multiple antennas, which are correlated in space. We employ maximal-ratio combining (MRC) scheme at the receiver and eavesdropper to combine the received signals. We assume that the main channel and the eavesdropper's channel undergo Nakagami-m fading with the fading parameters mB and mE, respectively. In this paper, we derive new closed-form expressions for the exact secrecy outage probability and the probability of positive secrecy. To verify the analytical results, we provide Monte Carlo simulations at the end.
In this paper, we study the secrecy performance of short packet secure communications over a fading wiretap channel when there are multiple receivers and eavesdroppers. In particular, we evaluate and compare the performance of colluding and non-colluding eavesdropping modes, in terms of achievable secrecy throughput. Our aim is to determine whether eavesdroppers' collusion degrades the average secrecy throughput compared to a non-colluding scenario. After deriving closed-form approximations on average secrecy throughput for both scenarios, Monte-Carlo simulations are performed to obtain the accuracy of each approximation. Our results reveal that the impact of colluding eavesdroppers on the average secrecy throughput causes more loss than a non-colluding case, especially with the increasing number. Besides, an increased number of receivers does not eliminate the negative impact of eavesdroppers.
In this paper, the physical-layer security for a three-node wiretap system model is studied. Under the threat of multiple eavesdroppers, it is presumed that a transmitter is communicating with a legitimate receiver. The channels are assumed to be following cascaded κ-μ fading distributions. In addition, two scenarios for eavesdroppers’ interception and information-processing capabilities are investigated: colluding and non-colluding eavesdroppers. The positions of these eavesdroppers are assumed to be random in the non-colluding eavesdropping scenario, based on a homogeneous Poisson point process (HPPP). The security is examined in terms of the secrecy outage probability, the probability of non-zero secrecy capacity, and the intercept probability. The exact and asymptotic expressions for the secrecy outage probability and the probability of non-zero secrecy capacity are derived. The results demonstrate the effect of the cascade level on security. Additionally, the results indicate that as the number of eavesdroppers rises, the privacy of signals exchanged between legitimate ends deteriorates. Furthermore, in this paper, regarding the capabilities of tapping and processing the information, we provide a comparison between colluding and non-colluding eavesdropping.
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.
On Physical Layer Security Over Fox's H-Function Wiretap Fading Channels
Most of the well-known fading distributions, if not all of them, could be encompassed by the Fox's H-function fading. Consequently, we investigate the physical layer security over Fox's H-function fading wiretap channels, in the presence of non-colluding and colluding eavesdroppers. In particular, for the non-colluding scenario, closed-form expressions are derived for the secrecy outage probability (SOP), the probability of non-zero secrecy capacity, and the average secrecy capacity. These expressions are given in terms of either univariate or bivariate Fox's H-function. In order to show the effectiveness of our derivations, three metrics are respectively listed over the following frequently used fading channels, including Rayleigh, Weibull, Nakagami-m, α - μ, Fisher-Snedecor (F-S) F, and extended generalized-K. Our tractable results are not only straightforward and general, but also feasible and applicable, especially the SOP, which is usually limited to the lower bound in the literature due to the difficulty of deriving closed-from analytical expressions. For the colluding scenario, a super eavesdropper equipped with maximal ratio combining (MRC) or selection-combining (SC) schemes is characterized. The lower bound of SOP and exact PNZ are thereafter derived with closed-form expressions in terms of the multivariate Fox's H-function. In order to validate the accuracy of our analytical results, Monte Carlo simulations are subsequently conducted for the aforementioned fading channels. One can observe that for the former non-colluding scenario, we have perfect agreement between the exact analytical and simulation results, and highly accurate approximations between the exact and asymptotic analytical results. On the contrary, the SOP and PNZ of colluding eavesdropper is greatly degraded with the increase of the number of eavesdroppers. Also, the so-called super eavesdropper with MRC is much powerful to wiretap the main channel than the one with SC.