With the continued development of optical wireless communications, the security performance of free space optical (FSO) communications is the most crucial aspect that should receive significant attention. Despite the fact that FSO communications are considered more secure than radio frequency systems, their link performance degrades due to some environmental factors such as atmospheric turbulence, fog, and non-zero boresight pointing errors. The combined effect of these factors on the secrecy performance of FSO communication systems over the generalized Malaga- M fading channel is investigated in this paper. This work assumes a more realistic eavesdropping scenario in which both legitimate and unauthorized receivers are located on the same receiving plane. Secrecy outage probability and strictly positive secrecy capacity are expressed in exact closed-form expressions in this work. The results show that the FSO system has acceptable secrecy performance in moderate and light fog, with potential reach distances ranging from hundreds of meters to a few kilometers. Monte-Carlo simulations are used to verify the numerical results.
With the continued development of optical wireless communications, the security performance of free space optical (FSO) communications is the most crucial aspect that should receive significant attention. Despite the fact that FSO communications are considered more secure than radio frequency systems, their link performance degrades due to some environmental factors such as atmospheric turbulence, fog, and non-zero boresight pointing errors. The combined effect of these factors on the secrecy performance of FSO communication systems over the generalized Malaga- M fading channel is investigated in this paper. This work assumes a more realistic eavesdropping scenario in which both legitimate and unauthorized receivers are located on the same receiving plane. Secrecy outage probability and strictly positive secrecy capacity are expressed in exact closed-form expressions in this work. The results show that the FSO system has acceptable secrecy performance in moderate and light fog, with potential reach distances ranging from hundreds of meters to a few kilometers. Monte-Carlo simulations are used to verify the numerical results.
The security issue is investigated from a physical layer perspective in the context of free-space optical (FSO) communications. More precisely, the performance of secure FSO link with intensity modulation/direct detection over Málaga (M) atmospheric turbulence channels that accounts for pointing errors is addressed in this letter. The closed-form expressions for the average secrecy capacity, the secrecy outage probability and the strictly positive secrecy capacity are derived by considering the specific nature of FSO channels modeled by the general M distribution. Monte-Carlo simulations are provided to verify the accuracy of our derivations.
With the deployment of hybrid RF-FSO networks, there exists the potential to contribute significantly to the evolving landscape of 6G communication, as it effectively addresses challenges pertaining to connectivity, capacity, and security. In this paper, we study the secrecy performance of hybrid radio frequency (RF) - free space optical (FSO) systems in the presence of an eavesdropper. To improve the reliability of the source-destination transmission process, we consider a source that can transmit data via both RF and FSO links, simultaneously. Specifically, the RF links are exposed to generalized α – μ fading channels, while the FSO link is subject to Málaga distributions. Therefore, we deduce the novel analytical expression of secrecy outage probability and verify the results with the Monte Carlo simulations. The outcomes underscore the pronounced impact of fading parameters, receiver detection techniques, pointing errors, and atmospheric turbulence on security performance.
In this paper, we numerically study the secrecy performance of the free-space optical (FSO) system by considering different eavesdropping scenarios. More precisely, we considered three possible eavesdropping scenarios for Eve : 1) Eve is between Alice and Bob ; 2) Eve and Bob are in the same receiving plane; 3) Eve is behind Bob . We adopt the Málaga ( M )-distribution channel to model atmospheric turbulence due to the presence of link blockage while considering the non-zero boresight pointing error and path loss. To do so, we obtain a novel probability density function (PDF) and cumulative distribution function (CDF) under different eavesdropping scenarios, based on which we derived the secrecy outage probability (SOP) analytical expressions as well as their asymptotic expressions at a high SNR regime. We verified the results using Monte Carlo simulations, which showed that the parameters related to atmospheric turbulence and pointing errors, as well as the location of the eavesdropper, have different effects on different eavesdropping scenarios.
The emergence of an array of new wireless networks has led researchers to evaluate the prospect of utilizing the physical properties of the wireless medium in order to design secure systems. In this paper, the physical layer secrecy performance of a mixed radio frequency-free space optical (RF-FSO) system with variable gain relaying scheme is investigated in the presence of an eavesdropper. We assume that the eavesdropper can wiretap the transmitted confidential data from the RF link only. It is further assumed that the main and eavesdropper RF links are modeled as generalized Gamma (GG) fading channel, and the free space optical (FSO) link experiences Málaga turbulence with pointing error impairment. Our primary concern is to protect this confidential information from being wiretapped. Besides pointing error, the atmospheric turbulence and two types of detection techniques (i.e. heterodyne detection and intensity modulation with direct detection) are also taken into consideration. Utilizing amplify-and-forward (AF) scheme, the novel mathematical closed-form expressions for average secrecy capacity, lower bound of secrecy outage probability, and strictly positive secrecy capacity are derived. As both the links (RF and FSO) undergo generalized fading channels, the derived expressions are also general. We present a unification of some existing works utilizing the proposed model to better clarify the novelty of this work. Finally, all the derived expressions are justified via Monte-Carlo simulations.
In this paper, the secrecy performance of the physical layer security (PLS) of the hybrid free-space optical/radio frequency (FSO/RF) communication system is analyzed. The transmission protocol of the considered system is performed under the eavesdropper's attempt to overhear the RF link between the transmitter and legitimate receiver of the hybrid system. The FSO link is characterized by Málaga-M distribution while the RF links are modeled by Nakagami-m distribution. The two practical eavesdropping modes considered in this paper include: colluding and non-colluding. Exact closed-form expressions for the system's secrecy outage probability (SOP), the asymptotic of the SOP (SOP∞), the probability of strictly positive secrecy capacity (SPSC), the average secrecy capacity (ASC), and the asymptotic of the ASC (ASC∞), are specifically derived under the influence of both eavesdropper modes. Our derived analytical expressions present an efficient tool to investigate the impact of some channel parameters on the secrecy performance, namely the fading severity of the RF links, atmospheric turbulence severity, pointing error of the FSO link, number of eavesdroppers, and the power of the eavesdropper links. The results show that the increase of the eavesdroppers' number under both modes profoundly degrades the considered system secrecy performance. The accuracy of the numerical results obtained is validated by Monte-Carlo simulations.
Abstract Free space optical (FSO) communication is a promising candidate for the next generation (5G and beyond) wireless communication systems, due to its merits (i.e. low latency, high data rate, and license‐free band, among others). However, atmospheric turbulence (AT) as well as pointing error (PE) are two of the main challenges with FSO communication that affect its performance. Here, the exact closed‐form expression of the average secrecy capacity and secrecy outage probability under the composite effect of AT and non‐zero boresight PEs is evaluated. For all the regimes of the AT (weak to strong), a generalised Malaga distribution is used to model the channel fading gain of the FSO link. The expressions are generalised and valid for all turbulence, and are applicable for intensity modulation direct detection as well as heterodyne detection techniques.