This paper proposes a secure amplify-and-forward (AF) relaying scheme in unmanned aerial vehicle (UAV) networks while accounting for the power consumption limitations of UAVs. Since a UAV's battery life is limited, we propose selecting the UAV relays based on their probability of availability, which we model to be a function of the UAV's power consumption model. Then, physical layer security is achieved by partitioning the limited available relays into information relaying UAVs and cooperative jammers while aiming to maximize the secrecy rate of the network when an eavesdropper is located in the vicinity of the destination node. Meanwhile, the information bearing relays use beamforming to enhance the information delivery to the destination, and the cooperative jamming relays use precoded artificial-noise scheme to degrade the eavesdropping links' received signal-to-noise ratios. Simulation results show significant secrecy rate enhancements when the proposed schemes are adopted compared to conventional relaying scenarios, especially when cooperative jamming is deployed.
This paper proposes a secure amplify-and-forward (AF) relaying scheme in unmanned aerial vehicle (UAV) networks while accounting for the power consumption limitations of UAVs. Since a UAV's battery life is limited, we propose selecting the UAV relays based on their probability of availability, which we model to be a function of the UAV's power consumption model. Then, physical layer security is achieved by partitioning the limited available relays into information relaying UAVs and cooperative jammers while aiming to maximize the secrecy rate of the network when an eavesdropper is located in the vicinity of the destination node. Meanwhile, the information bearing relays use beamforming to enhance the information delivery to the destination, and the cooperative jamming relays use precoded artificial-noise scheme to degrade the eavesdropping links' received signal-to-noise ratios. Simulation results show significant secrecy rate enhancements when the proposed schemes are adopted compared to conventional relaying scenarios, especially when cooperative jamming is deployed.
This paper proposes a novel cooperative secure unmanned aerial vehicle (UAV) aided transmission protocol, where a source sends confidential information to a destination via an energy-constrained UAV-mounted amplify-and-forward relay in the presence of a ground eavesdropper. We adopt destination-assisted cooperative jamming as well as simultaneous wireless information and power transfer at the UAV-mounted relay to enhance physical-layer security and transmission reliability. Assuming a low-altitude UAV, we derive connection probability, secrecy outage probability, instantaneous secrecy rate, and average secrecy rate of the proposed protocol over Air-Ground channels, which are modeled as Rician fading with elevation-angel dependent parameters. Further, we analyze the asymptotic average secrecy rate performance of the proposed UAV-relaying scheme and derive high signal-to-noise ratio measures of the average secrecy rate to highlight the effect of various channel features on the system performance. By simulations, we verify our novel theoretical exact and approximate results and demonstrate significant performance improvement of our protocol, when compared to conventional transmission protocol with ground relaying and UAV-based transmission protocol without exploiting destination jamming. Finally, we evaluate the impacts of various system parameters, specifically, find the optimal UAV placement on the proposed protocol in terms of the aforementioned secrecy metrics.
Unmanned aerial vehicle (UAV) communication is one of the enabling technology in the 5G/B5G era, which has received extensive research attention recently. In this paper, we consider a UAV employing amplify-and-forward protocol to facilitate the secure transmissions for a legitimate user pair, where the direct link is not available. In order to protect the legitimate transmissions and prevent the eavesdropper from intercepting the source message, the legitimate receiver launches a jamming signal to confuse the eavesdropper. In this regard, the optimal jamming power and UAV placement are jointly investigated towards the highest secrecy rate. For this problem, we first propose an efficient power control scheme based on bi-section search with fixed UAV placement. Then, a deep neural network (DNN) is constructed and trained based on the data from exhaustive search in order to determine the best UAV placement. Through numerical simulations, we verify that the trained DNN effectively approximates the optimal UAV placement, also demonstrated is the evident superiority of our proposed scheme as compared to the baselines in terms of security performance.
In this letter, we propose a novel scheme to improve physical layer security for amplify-and-forward (AF) relay networks with two-hop information leakage. Unlike traditional joint cooperative beamforming (CB) and cooperative jamming (CJ) design, where mere artificial noise (AN) is exploited by the jammers to degrade eavesdroppers' channels, in our proposed scheme, the jammers send AN along with the confidential signal to simultaneously confuse the eavesdroppers and enhance the quality of received signals at the destination. In particular, the CB vectors and AN covariance matrix are jointly optimized for the relays and jammers under individual power constraints. By decoupling this resultant design problem, suboptimal solutions are obtained using the semidefinite relaxation technique. Simulation results are also provided to demonstrate that the proposed scheme has an obvious advantage in enhancing the secrecy rate.
The broadcast nature of wireless channels introduces significant security vulnerabilities in information transmission, particularly when the eavesdropper is close to the legitimate destination. In such scenarios, the eavesdropping channel often exhibits high spatial correlation with, or even superior quality to, the legitimate channel. This makes it challenging for traditional power optimization methods to effectively suppress the eavesdropping rate. To address this challenge, this paper proposes an optimization method for the secrecy capacity of unmanned aerial vehicle (UAV) relaying based on the dynamic adjustment of the power allocation factor. By injecting artificial noise (AN) during signal forwarding and combining it with real-time channel state information, the power allocation factor can be dynamically adjusted to achieve precise jamming of the eavesdropping link. We consider a four-node communication model consisting of a source, a UAV, a legitimate destination, and a passive eavesdropper, and formulate a joint optimization problem to maximize the secrecy rate. Due to the non-convexity of the original problem, we introduce relaxation variables and apply successive convex approximation (SCA) to reformulate it into an equivalent convex optimization problem. An analytical solution for the power allocation factor is derived using the water-filling (WF) algorithm. Furthermore, an alternating iterative optimization algorithm with AN assistance is proposed to achieve global optimization of the system parameters. Simulation results demonstrate that, compared to traditional power optimization schemes, the proposed algorithm substantially suppresses the eavesdropping channel capacity while enhancing transmission efficiency, thereby significantly improving both secrecy performance and overall communication reliability.
This letter studies the Unmanned Aerial Vehicles (UAVs)-assisted proactive eavesdropping in the suspicious amplify-and-forward multi-relay system, where the suspicious transmitter based on opportunistic relaying protocol selects one best suspicious relay to communicate with the suspicious destination. In addition, we assume each UAV hovers over one specific relay for the purpose of jamming or eavesdropping, which is only valid for this relay due to the limited coverage of the UAVs and the dispersion between these relays. Moreover, the UAVs used for jamming cannot implement eavesdropping concurrently due to the half-duplex constraints. Under this setup, with detailed analysis and strict proof, we find an interesting trade-off in deciding the number of UAVs used for jamming: jamming with more UAVs helps decrease the suspicious rate to facilitate the eavesdropping by remaining UAVs, but is at the cost of degrading the precondition of successful eavesdropping. Numerical results verify this trade-off and show that with simple one-dimensional search, the proposed jamming-assisted strategy achieves significant gain compared to conventional passive eavesdropping.
In this paper, we investigate the secrecy performance of cooperative wireless communication networks, where a source (Alice) intends to transmit information to a legitimate user (Bob) with an unmanned aerial vehicle (UAV) enabled friendly jammer in the presence of a passive eavesdropper (Eve). In order to maximize the secrecy rate of the system under a certain secrecy outage probability, we design a scheme utilizing artificial-noise (AN) beamforming and cooperative jamming to determine the optimal power allocation factor with only location and statistical channel state information of the Eve. Numerical results validate that the proposed scheme can significantly improve the secrecy rate and secure energy efficiency (EE) performance.