The zero-outage secrecy with energy harvesting is considered in short packet IoT-aided cellular cooperative networks using the inspired non-orthogonal multiple access (NOMA) strategy. The scheme ensures zero-outage secrecy through two cooperative transmissions: one for only artificial noise (AN) and another for both the artificial noise and the secure message. To ensure that only legitimate users can decode the message while the eavesdropper’s probability of success remains zero, which is so-called zero-outage secrecy, the scheme additionally employs the reverse training strategy to prevent the channel state information leakage to the eavesdroppers. The results show that the proposed scheme can achieve zero-outage secrecy for both IoT and cellular messages even in the case the eavesdroppers take advantage in their location or large number of antennas so that their channels become powerful. When forwarding the secure cellular message, the master IoT node imposes the IoT message using such a large amount of harvested power that the IoT user can achieve the highest zero-outage secrecy throughput and energy efficiency, there is not much loss in the zero-outage secrecy throughput obtained at the cellular user. It also highlights that when the transmit power increases, the zero-outage secrecy throughput also increases, indicating the practical implementation of the proposed scheme.
The zero-outage secrecy with energy harvesting is considered in short packet IoT-aided cellular cooperative networks using the inspired non-orthogonal multiple access (NOMA) strategy. The scheme ensures zero-outage secrecy through two cooperative transmissions: one for only artificial noise (AN) and another for both the artificial noise and the secure message. To ensure that only legitimate users can decode the message while the eavesdropper’s probability of success remains zero, which is so-called zero-outage secrecy, the scheme additionally employs the reverse training strategy to prevent the channel state information leakage to the eavesdroppers. The results show that the proposed scheme can achieve zero-outage secrecy for both IoT and cellular messages even in the case the eavesdroppers take advantage in their location or large number of antennas so that their channels become powerful. When forwarding the secure cellular message, the master IoT node imposes the IoT message using such a large amount of harvested power that the IoT user can achieve the highest zero-outage secrecy throughput and energy efficiency, there is not much loss in the zero-outage secrecy throughput obtained at the cellular user. It also highlights that when the transmit power increases, the zero-outage secrecy throughput also increases, indicating the practical implementation of the proposed scheme.
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.
This paper studies the secure communications of a wireless-powered full-duplex cooperative non-orthogonal multiple access (CoNOMA) system with a source node, a group of near users, a far user and an external eavesdropper. In particular, the eavesdropper intends to wiretap the transmitted signals from the source. Two of the near users are picked up, served as a wireless-powered relay and a wireless friendly jammer, respectively. We propose a user selection and cooperative jamming based secure transmission scheme. Specifically, the source transmits a superimposed signal to the selected near user. The selected near user, who is employed as a relay, can harvest energy from the radio frequency signals and decode the information simultaneously. The harvested energy are then utilized to forward the signal to the far user. The jammer also collects energy from the source, and emits artificial noise by using the harvested energy to confuse the eavesdropper. Based on the proposed scheme, the closed-form expression for secrecy outage probability (SOP) and effective secrecy throughput (EST) are derived. The correctness of our theoretical analysis is verified by Monte-Carlo simulations, and the superiority of the proposed scheme in improving the system secure performance is also validated.
Non-orthogonal multiple access (NOMA) is an important technology for the forthcoming 5G 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 expressions of secrecy outage probability (SOP) are derived. 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.
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.
In this paper, secure communication in non-orthogonal multiple access (NOMA) downlink system is considered wherein two NOMA users with channel gain difference are paired in each transmission slot. The user with poor channel condition (weak user) is entrusted, while the user with good channel condition (strong user) is a potential eavesdropper. The weak user data can be intercepted by the strong user since the strong user needs to decode the weak user’s message for successive interference cancellation operation in NOMA. To impair strong user’s eavesdropping capability, weak user’s information-bearing signal is merged with an artificial signal (AS). Thus, the eavesdropping process requires extra decoding step at higher power level. The secrecy outage probability of the weak user is derived and provided in closed-form expression. The weak user faces a choice between transmitting the information-bearing signal with the total power and the deploying the AS technique, whereas the strong user can choose whether to eavesdrop the weak user’s message or not. To investigate users’ power-secrecy tradeoffs, their interactions are modeled as a non-cooperative zero-sum game. The existence of Nash equilibria (NEs) of the proposed game is first analyzed, and pure and mixed-strategy NE profiles are provided. In addition, numerical simulations are conducted to validate the analytical results and to prove that AS-Aided proposed scheme enhances the secrecy performance of NOMA systems while maintaining the NOMA superiority over OMA systems.
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.