To enhance the security of unmanned aerial vehicle (UAV) communication system with delayed channel state information (CSI), two physical layer security schemes based on 3D beamforming are propsed, namely destination-specific (DS) scheme and eavesdropper-null (EN) scheme. Through 3D beamforming, the UAV carries out beamforming design in horizontal and vertical directions, which improves the safety degree of freedom. The expressions of secrecy outage probability about two schemes are derived, and the influence of system parameters on the secrecy outage probability is studied. Simulation results verify that the 3D beamforming schemes can greatly reduce the secrecy outage probability and improve the security of UAV communication system.
To enhance the security of unmanned aerial vehicle (UAV) communication system with delayed channel state information (CSI), two physical layer security schemes based on 3D beamforming are propsed, namely destination-specific (DS) scheme and eavesdropper-null (EN) scheme. Through 3D beamforming, the UAV carries out beamforming design in horizontal and vertical directions, which improves the safety degree of freedom. The expressions of secrecy outage probability about two schemes are derived, and the influence of system parameters on the secrecy outage probability is studied. Simulation results verify that the 3D beamforming schemes can greatly reduce the secrecy outage probability and improve the security of UAV communication system.
In this paper, we study secure cooperative transmission for the multiple-input-single-output multiple-eavesdropper (MISOME) systems, where a source (Alice) aims to send confidential messages to a legitimate user (Bob) with the aid of an unmanned aerial vehicle (UAV) enabled friendly jammer (Charlie) in the presence of multiple eavesdroppers (Eves). To further guarantee the secrecy performance, artificial noise (AN) beamforming together with cooperative Jamming (CJ) has been utilized in this considered system with only location and statistical channel state information of the Eves. Specifically, taking imperfect channel state information (CSI) between Charlie and Bob into account, we derive the exact closed-form expression of the secrecy outage probability (SOP) and develop an efficient scheme to solve the secrecy rate maximization (SRM) problem which has been verified as a convex one under certain SOP. Moreover, we propose an optimal UAV placement strategy to further enhance secrecy performance. The numerical results are provided to validate that the system security would seriously degenerate with channel uncertainty. Besides, the proposed scheme is verified to outperform the terrestrial CJ scheme in improving the secrecy rate and secure energy efficiency (EE) performance under perfect CSI or tolerable channel estimation errors. Finally, the effectiveness of the proposed UAV placement strategy in enhancing transmission security and the applicability of the proposed scheme has also been demonstrated.
Although unmanned aerial vehicles (UAVs) are enabling various applications in military, public, and commercial fields, the issue of information security in UAV communications is a critical issue which hinder the extensive applications of the UAVs. To cope with this issue, physical layer security is an alternative security technology, which can enhance the information security by flexibly adjusting transmission strategies and parameters to accommodate the channel changes. In this paper, the information security of the UAV communications is investigated from the perspective of physical layer security. The ground-to-air communications are considered under the presence of eavesdroppers, while the UAV can operate in a full-duplex mode so that it can perform cooperative jamming to confuse the eavesdroppers. The achievable secrecy rate of the UAV networks is maximized by the joint designs of the transmit precoding and cooperative jamming. To this end, an intractable optimization problem is formulated, and a solution scheme is proposed by using the approaches of equivalent transformation and alternating optimization. Simulation results demonstrate that the proposed scheme achieves a notable improvement in secrecy rate.
Unmanned aerial vehicles (UAVs) will be extensively utilized in various Internet of Things (IoT) scenarios due to their flexible mobility and rapid on-demand deployment. It becomes necessary and urgent to investigate the secrecy performance of the UAV IoT communication systems because of the open characteristics of wireless channels. In this article, the physical layer security of UAV IoT communication systems is studied, in which a ground IoT device transmits some confidential messages to a UAV hovering in the air, while a random number of eavesdroppers are randomly positioned around the ground source. The ground-to-air channel is assumed to experience Rician fading for the case of line-of-sight propagation and Rayleigh fading for the case of nonline-of-sight propagation, respectively. In addition, in order to improve the security of the system, we also investigate the secrecy performance of the UAV IoT system with a friendly UAV that generates jamming signals to distract the eavesdroppers. Utilizing the stochastic geometry theory, the cumulative distribution functions for the signal-to-interference-plus-noise ratio of the main and eavesdropping links are derived, and then the analytical expressions of the secrecy outage probability and the average secrecy rate are obtained. Finally, the accuracy of the analytical results is verified by Monte Carlo simulation.
With the notable interest in unmanned aerial vehicle (UAV)-to-ground communications, new fading channel models that take into account the effects of shadowing have been proposed for beyond 5G networks. Guaranteeing physical layer security of the UAV-to-ground channels is essential for the transmission of confidential messages in the presence of an eavesdropper. In this paper, we examine physical layer security metrics, such as the average secrecy capacity, the secrecy outage probability, and the probability of strictly positive secrecy capacity, in UAV-to-ground communications with shadowing. Monte Carlo simulations are performed to verify the analytical expressions. Finally, the effect of the fading parameters on the system performance is studied.
Owing to flexible management and low overhead, wireless physical layer security (PLS) has been applied to support many critical applications (e.g., data dissemination) of unmanned aerial vehicles (UAVs)-based mobile communication networks in emergency scenarios. Although the impact of static network scenarios or receiver mobility on PLS has been well studied, there is no much work that studies the impact of UAV-based transmitter mobility on PLS. To fill this gap, in this paper, we investigate PLS of a scenario, where a random mobile UAV-based transmitter transmits information to a static ground entity under Rayleigh fading channel. More specifically, we consider a communication system, in which a mobile UAV hovers over a region to collect information and then disseminates this information to a static ground network entity in a confidential manner under the presence of an eavesdropper. Because of popularity and practicality, the UAV is assumed to hover following the random way point (RWP) mobility model. We investigate the secrecy characteristics of the UAV under steady running state in terms of ergodic secrecy capacity (ESC), positive secrecy capacity probability (PSCP) and secrecy outage probability (SOP) for the communication between the UAV and the receiver. We then investigate the secrecy performance of the proposed system while considering the pause time of the RWP mobility model adopted by the UAV. We further extend our proposed theoretical model to other realistic scenarios, including the presence of multiple cooperative and non-cooperative eavesdroppers, and study the PSCP and SOP metrics of the corresponding system. Furthermore, we propose three types of secrecy improvement strategies for the considered communication model. We strike a good trade-off between the secrecy improvement and transmit outage probability. Extensive simulations have been conducted to validate our theoretical analysis as well as the effectiveness of the proposed secrecy improvement strategies.
Unmanned aerial vehicles (UAVs) have been extensively utilized in various scenarios due to their flexible mobility and rapid on-demand deployment. It becomes necessary and urgent to examine the secrecy performance of the UAV communication systems due to the open characteristics of the transmission technologies employed in UAV systems. In this paper, we investigate the physical layer security of the UAV communication system, in which the ground base station sends secret messages to the UAV hovering in the air, while a random number of eavesdroppers are randomly located around the ground base station. Using the Poisson point process theory, we obtain the exact and approximate expressions of the cumulative distribution function for the signal-to-noise ratio of the ground-to-air link, and then the analytical expressions of the secrecy outage probability and the average secrecy rate are derived. Finally, the accuracy of the analytical results is validated by Monte Carlo simulation.