In this paper we review the secrecy performance of cooperative non orthogonal multiple access networks at the BS for both a single-antenna and multiple-antenna for downlink and Uplink scenario. A preserved zone, also called as a wire tapper prohibition zone, is applied in all cases to improve the PLS. In the multiple-antenna aided situation, we also look at the generated noise at the BS to see if we can improve the secrecy performance even more. PLS is used to improve the secrecy performance of wireless communication systems while also increasing their bandwidth.
In this paper we review the secrecy performance of cooperative non orthogonal multiple access networks at the BS for both a single-antenna and multiple-antenna for downlink and Uplink scenario. A preserved zone, also called as a wire tapper prohibition zone, is applied in all cases to improve the PLS. In the multiple-antenna aided situation, we also look at the generated noise at the BS to see if we can improve the secrecy performance even more. PLS is used to improve the secrecy performance of wireless communication systems while also increasing their bandwidth.
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, 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) aspects of the uplink cooperative non-orthogonal multiple access (NOMA) in the context of two user scenario. More specifically, this work employs the decode-and-forward (DF) relay for not only establishing a connection between the far user and base station (BS) but also enhancing the performance of far user whose channel is prone to the detrimental effects of fading and shadowing. The secrecy performance comparison between two users i.e., near user and far user is obtained under perfect and imperfect successive interference cancellation (SIC) assumptions and even the performance of FU is improved by using DF relay and instantaneous channel gain decoding order is considered at the BS under two cases. This paper analyses the performance of cooperative uplink NOMA network in the presence of an external eavesdropper in terms of secrecy ergodic capacity (SEC), secrecy ergodic sum capacity (SESC), and secrecy outage probability (SOP). This work derives the closed-form analytical expressions of SOP and SEC metrics for both strong and weak users with perfect and imperfect SIC cases in order to characterise the secrecy performance of the proposed secure cooperative NOMA network. Further, the outcomes of the simulations are shown as evidence for both the validation of the mathematical analysis and the performance of the proposed method.
A novel secrecy scenario of uplink non-orthogonal multiple access (NOMA) along with cooperative jammer(s) to improve secrecy performance is studied in this work. We first characterize secrecy performance in terms of positive secrecy rate probability, secrecy outage probability (SOP) and effective secrecy throughput (EST), and derive the closed-expressions of individual secrecy performance. The analytical results not only show an improvement on secrecy performance with the aid of cooperative jamming, but also clearly illustrate how each jammer affects the secrecy performance. We then continue the study of the individual secrecy performance for its asymptotic behaviors, and reveal it is only dependent on its relative distance to the eavesdropper over the desired receiver in a high signal-to-noise ratio (SNR) regime. Finally, the maximization of overall secrecy performance is covered by investigating two optimization problems: 1) optimal selection of jammer(s) under the same transmit power; 2) optimal power allocation to each transmitter, including jammers, under the constraint of limited total transmit power. The solutions to these two problems are presented and demonstrated by an appropriate case.
The prominence of the wireless communication has been urging the monotonically increasing demand of security and privacy. In wireless systems, the notion of perfect secrecy of information with respect to illegitimate nodes can be ensured via physical layer security (PLS) techniques. Unfortunately, they can be made less effective if source- eavesdropper wiretap channel is better than the main source-receiver channel. The various node cooperation schemes can be employed to combat this limitation where a relay node assists the communication to improve the performance significantly. In this paper, a four node wireless communication system consisting of a source, a destination, a relay and an eavesdropper as wire-tapper has been considered. The performance of the traditional cooperation schemes in terms of secrecy rate has been investigated with a different scenario where relay node helps the eavesdropper to deteriorate the secrecy rate. In addition, since legitimate receiver can overhear the transmission of relay, it favours the achievable secrecy rate. We formulate an analytical expression of conditional secrecy outage probability for the investigated system. From the obtained simulation results, it has been observed that secrecy rate is monotonically increases with path loss index. Furthermore, the proper selection of the system parameters leads to enhance the secrecy performance of the system even if relay pertains to degrade the performance. Amplify-and-forward, cooperation, decode-and-Forward, secrecy rate, relay.
With the increasing demand for security in many sectors, such as defense and health systems, developing secure Internet of Things (IoT) networks is a matter of great urgency. Looking at a potential solution for secure IoT systems, we investigate the physical layer security of cooperative nonorthogonal multiple access (NOMA) systems. After decoding information signal, the idea that a strong IoT node can serve as a relay node for other weak IoT nodes in enhancing their signal reception reliability, is known as cooperative NOMA. We consider both single-antenna and multiantenna aided transmission scenarios, where the base station (BS) communicates with two IoT nodes of different strengths. In the multiantenna scenario, artificial noise (AN) is generated at the BS and the strong IoT node for improving the security of the system. In order to characterize the secrecy performance, we derive new exact expressions of the security outage probability for both the IoT nodes under both the single-antenna and multiantenna aided scenarios. For the single-antenna scenario, we show that the power optimization at the BS and the strong IoT node can enhance the secrecy performance to some extent. For this case, we further study the secrecy diversity order of the overall system, which is mainly determined by the IoT node with the worse channel condition. For the multiantenna scenario, we derive the asymptotic secrecy outage probability (SOP) when the number of antennas tends to infinity. Extensive simulations have been conducted to verify the accuracy and effectiveness of the proposed analytical derivations. The presented results verify that the security performance of the cooperative NOMA-based IoT network can be improved through an appropriate power control scheme and by generating AN at the BS and the strong IoT node. The simulation results further illustrate that the asymptotic SOP is close to the exact one.