This study explores the physical layer security (PLS) analysis of a downlink non-orthogonal multiple access (NOMA) network under multiple eavesdropping scenarios. A composite NOMA signal is transmitted to the users enabling the users for collaborative decoding of their signals using successive-interference-cancellation (SIC). A jammer (J) node is strategically deployed to transmit the interference signals to the eavesdroppers (Eave) in the network. Additionally, the secrecy performance analysis was performed employing various jamming schemes like absence-of-jamming (AJ), unknown-jamming (UJ), and known-jamming (KJ) under both collaborative (C) and non-collaborative (NC) eavesdropping scenarios. Notably, the simulation results reveal the enhanced secrecy rates in the scenario of NC for KJ scheme making it the remarkable choice to improve the confidentiality in the network. Finally, this paper underscores KJ as a significant approach for these networks.
This study explores the physical layer security (PLS) analysis of a downlink non-orthogonal multiple access (NOMA) network under multiple eavesdropping scenarios. A composite NOMA signal is transmitted to the users enabling the users for collaborative decoding of their signals using successive-interference-cancellation (SIC). A jammer (J) node is strategically deployed to transmit the interference signals to the eavesdroppers (Eave) in the network. Additionally, the secrecy performance analysis was performed employing various jamming schemes like absence-of-jamming (AJ), unknown-jamming (UJ), and known-jamming (KJ) under both collaborative (C) and non-collaborative (NC) eavesdropping scenarios. Notably, the simulation results reveal the enhanced secrecy rates in the scenario of NC for KJ scheme making it the remarkable choice to improve the confidentiality in the network. Finally, this paper underscores KJ as a significant approach for these networks.
This article explores the issue of physical layer security (PLS) through an analysis of a Non-Orthogonal Multiple Access (NOMA) network using multiple jamming strategies. In this network, a source transmits multiplexed signals to NOMA users when Eve is present. A jammer node adds interference signals to prevent Eve from wiretapping the secret information of the NOMA users. By deploying a new control-jammer (CJ) strategy to this network, it is possible to maximize secrecy rate at both NOMA users while working under a total power constraint. The main focus of the proposed work is on evaluating the PLS analysis of the network in terms of secrecy rate, with particular attention to the CJ condition. Additionally, the study measures the security performance difference between CJ and other jamming methods. Notably, the simulation findings confirm that CJ is effective in boosting the security of the NOMA network compared with other jamming strategies.
In this paper, we investigate the secrecy performance of an uplink-downlink power domain non-orthogonal multiple access (PD-NOMA) system with imperfect successive interference cancellation (SIC) in physical layer security (PLS). In the proposed system, two source users (SUs) communicate with two destination users (DUs) with the help of a cluster of multi-relay nodes using the decode-and-forward (DF) protocol in the presence of multi-eavesdroppers. These eavesdroppers try to overhear the wireless signal around the DUs. In our system, the selected DF-relay node also works as a jammer to improve security and protect confidential information from multi-eavesdroppers. In this role, the DF-relay node generates a jamming signal, creating artificial interference to reduce the quality of the eavesdropping channels. To evaluate the secrecy performance of the system, we derived the analytical expressions of the secrecy outage probability (SOP) for both DUs using three relay selection strategies over Rayleigh fading channels and used Monte Carlo simulations to confirm the accuracy of our calculations. Furthermore, we examined the effects of system parameters such as the number of eavesdroppers and DF relaying nodes, the power allocation, SIC performance, the position of eavesdropper on the SOP of the two DUs. We compared the performance of our proposed NOMA system with those of conventional orthogonal multiple access (OMA) schemes.
This paper investigates the physical layer security (PLS) of non-orthogonal multiple access (NOMA)-enabled overlay cognitive radio networks (NOMA-OCRNs), considering multiple non-colluding eavesdroppers. Here PLS is evaluated in terms of: (i) secrecy outage probability (SOP) of primary user (PU) and secondary user (SU) and (ii) system SOP (SSOP), system secrecy throughput (SST) and secrecy energy efficiency (SEE) of the network. Residual hardware impairments arising from non-ideal hardware and imperfect successive interference cancellation conditions are considered. Firstly, we derive new analytical expressions for the SOPs of PU and SU. Numerical evaluation results show that both PU as well as SU suffer very high SOPs that tend to unity in the high transmit power region. Further, RHI and i-SIC have a significant impact on the secrecy performance. To improve the PLS performance, we propose a jamming-assisted framework and develop novel analytical models for determining the SOPs of PU and SU. We derive the asymptotic SOP expressions as well. Detailed analytical and simulation results are presented to demonstrate that the proposed jamming-assisted framework leads to a significant reduction of the SOPs of both PU and SU while exhibiting considerable enhancement of SST and SEE of the network compared to the no-jammer scenario. In the final part of this paper, we utilize a deep learning framework for the precise and fast prediction of the SOPs of PU and SU, that can replace complex mathematical modeling.
We have proposed and analyzed secrecy performance of a network architecture which contains a source, two destinations, a friendly jammer (FJ) and an eavesdropper (Eve). To jam the Eve in order to secure the confidential information of both users, the FJ sends a jamming signal while the source sends the combined information signal using non-orthogonal multiple access (NOMA) technique to both the users. A known jamming is considered which is known by both the users. Both the users subtract the known jamming from the received signal and then decode the information signal as per the NOMA technique. We analyzed the physical layer security of the network in terms of the secrecy outage probability (SOP) where the two users have different target secrecy rates. A closed form expression of the SOP is developed. We have analyzed the SOP under the impact of several numerical parameters such as: source transmit signal to noise ratio (SNR), FJ transmit SNR, fraction of source transmit power, and different target secrecy rates. For a fixed transmit SNR of the FJ, we obtain an optimal value of the source transmit SNR at which SOP is minimized. These analyzed results are also supported by the MATLAB based simulation results.
NOMA (Non-Orthogonal Multiple Access) has been recognized as new multiple access technology for wireless communication networks of the fifth generation and beyond, owing to its ability to improve spectral efficiency, support massive connectivity, and provide user fairness. However, it has been observed that the superposition-based transmission principle of NOMA is highly susceptible to eavesdropping attacks, especially in an open wireless network where all wireless communications are inherently broadcast in nature. Hence, ensuring secure wireless communications for NOMA systems has now become an important area of research. This research aims to improve the secrecy level of wireless communications for NOMA systems by employing Physical Layer Security (PLS) techniques. Specifically, two prominent PLS techniques, Artificial Noise (AN) and Cooperative Jamming (CJ), have been employed to provide security against passive eavesdropping attacks. The cooperative NOMA system architecture is considered, and the secrecy enhancement is analyzed for two possible scenarios when the eavesdropper is close to the relay node and when the eavesdropper is close to the base station. The secrecy performance of the proposed system is analyzed through various parameters, namely, Secrecy Outage Probability (SOP), Secrecy Capacity (SC), Secrecy Rate (SR), and Secrecy Energy Efficiency (SEE) in terms of the Signal to Noise Ratio (SNR). The numerical results for the secrecy metrics are obtained through MATLAB-based simulations, whereas the system-level model is developed using the Simulink platform to verify the suggested system's functionality in the presence of AN and CJ for the legitimate NOMA users and the eavesdropper. The results show that the secrecy performance is significantly enhanced with the introduction of AN and CJ, and the system shows robust performance in terms of energy efficiency. This paper provides significant insights into the design of the NOMA system from the secrecy perspective and validates the potential of PLS techniques for the design of the future wireless system.
Physical layer security of a composite network, which includes both the uplink and downlink non-orthogonal multiple access (NOMA) system, has been analyzed. In this network, the relay is working as interface between the uplink and downlink NOMA system. Due to deep fading and shadowing, two legitimate destinations and the eavesdropper (EAV) are able to receive the information signals from the relay only. We have considered a scenario at the relay in which the relay decodes the strongest signal first when it does not know the transmit power of the information signals. To secure the confidential information, the jammer has been considered to secure the information from the EAV. For the considered model, the secrecy outage probability is analyzed as a performance metric using MATLAB based simulation. The optimal value of the relay transmit signal to noise ratio and the worst value of the transmit signal to noise ratio of the source one is indicated.