In this paper, we analyze the secrecy performance of a cooperative communication wireless system using nonorthogonal multiple access (NOMA) over α - μ fading channel. A new cooperative NOMA scheme is proposed to protect the confidential communication that is transmitted from a source to two users by the help of a relay under the monitoring of an eavesdropper (EAV). In particular, the legitimate user generates jamming signals to the EAV while the source transmits the signals to the relay and the source sends jamming signals to the EAV while the relay forwards the signals to the users. In order to evaluate the secrecy performance, the physical layer security (PLS) in term of the secrecy outage probability (SOP) for the active protection scheme (APS) is investigated and compared to that for a benchmark non-protection scheme (NPS). Simulation results show that the APS can effectively enhance the secrecy performance.
In this paper, we analyze the secrecy performance of a cooperative communication wireless system using nonorthogonal multiple access (NOMA) over α - μ fading channel. A new cooperative NOMA scheme is proposed to protect the confidential communication that is transmitted from a source to two users by the help of a relay under the monitoring of an eavesdropper (EAV). In particular, the legitimate user generates jamming signals to the EAV while the source transmits the signals to the relay and the source sends jamming signals to the EAV while the relay forwards the signals to the users. In order to evaluate the secrecy performance, the physical layer security (PLS) in term of the secrecy outage probability (SOP) for the active protection scheme (APS) is investigated and compared to that for a benchmark non-protection scheme (NPS). Simulation results show that the APS can effectively enhance the secrecy performance.
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.
In this paper, the secrecy performance for a downlink cooperative non-orthogonal multiple access (NOMA) communication system is studied under two cases. In the first case, the presence of an untrusted user is studied. While, the presence of an eavesdropper node is considered in the second case. The base station transmits superimposed information signals to the half-duplex two-way relay node. The relay amplifies-and-forwards the received signal towards the users. This paper studies the effectiveness of two factors on the secrecy performance in terms of secrecy capacity. these factors are the power allocated for each user, and the distance between the untrusted user and the cooperative relay node with respect to the strong user. Moreover, this paper proposes the shared jamming signal strategy in order to enhance the physical layer security of the cooperative NOMA in the presence of an eavesdropper node. Furthermore, simulations of the secrecy capacity are presented and compared with a conventional scheme based on null-steering jamming scheme. Based on the result the proposed technique outperforms the conventional technique in terms the of secrecy capacity.
Differentsystemmodels utilizing nonorthogonal multiple access (NOMA) have been successfully studied to meet the growing capacity demands of the Internet of Things IoT) devices for the next-generation networks. However, analyzing the antieavesdropping for NOMA systems under different scenarios and settings still needs further exploration before it can be practically deployed. Therefore, in this article, we study the secrecy performance of a cooperative NOMA system in the IoT networks where two source nodes communicate with their respective destination nodes via a common relay in the presence of an eavesdropper. Specifically, two source nodes send their data in parallel over the same frequency band to the common relay node using uplink NOMA. Then, the relay node forwards the decoded symbols to the respective destination nodes using downlink NOMA in the presence of an eavesdropper. To enhance the security performance of the considered system, we study and propose an artificial noise (AN)-aided scheme in which the two destination nodes emit a jamming signal to confuse the eavesdropper while receiving the signal from the common relay node. We also study the effect of NOMA power allocation, perfect successive interference cancellation (pSIC), and imperfect successive interference cancellation (ipSIC) on the considered system. Analytical expressions for the ergodic capacity (EC), ergodic secrecy sum rate (ESSR), and secrecy outage probability (SOP) are mathematically derived and verified with the simulation results. Our results demonstrate that a significantly higher ESSR and lower SOP of the system can be attained compared to a conventional NOMA system without a destination-assisted jamming signal scheme.
In this paper, we study the secrecy outage probability (SOP)and the strictly positive secrecy capacity (SPSC)of cooperative non-orthogonal multiple access (NOMA)system with a single antenna over Rayleigh fading channel in which there are a source, a relay node, two destinations and one eavesdropper. The relay adopts amplify-and-forward (AF)and decode-and-forward (DF)relaying schemes. The SOP and SPSC performance are analyzed to evaluate the level of security granted to legitimate users for both AF and DF protocols. The effects of the optimal power allocation value on system performance are also discussed and provided through numerical results.
Non-orthogonal multiple access (NOMA) is an important technology for the forthcoming 5 G and beyond. However, its privacy often suffers from adversarial eavesdropping, especially for the users with higher transmit power. In this paper, we propose a jamming-aided secure transmission scheme for cooperative NOMA networks with a full-duplex (FD) relay. In this scheme, two pairs of users perform secure transmission with the help of a decode-forward (DF) relay, which forwards information and generates artificial jamming to counteract eavesdropping. The precoding vectors are designed to zero-force the artificial jamming at legal receivers. Then, the channel statistics are calculated, based on which the secrecy rates of legitimate signals are analyzed and the expressions of secrecy outage probability (SOP) are derived. Furthermore, three benchmark schemes are also presented with their performance analyzed to verify the advantage of the proposed scheme. Simulation results show the accuracy of our analysis, and demonstrate that the proposed scheme can effectively reduce the SOP and improve the effective secrecy throughput via artificial jamming and FD relaying.
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.