Full duplex (FD) is one of the most attractive technologies in enhancing spectrum efficiency for potentially doubling the system throughput. In this work, we employ FD jamming to improve the secrecy performance of an uplink non-orthogonal multiple access (NOMA) system at the presence of one eavesdropper. We first characterize the individual secrecy performance in terms of effective secrecy throughput (EST), and derive its closed-form expression via secrecy outage probability (SOP). We then further investigate the problem of optimal power allocation to maximize overall secrecy performance. The solution to the optimization problem is figured out and demonstrated numerically with an appropriate case.
Full duplex (FD) is one of the most attractive technologies in enhancing spectrum efficiency for potentially doubling the system throughput. In this work, we employ FD jamming to improve the secrecy performance of an uplink non-orthogonal multiple access (NOMA) system at the presence of one eavesdropper. We first characterize the individual secrecy performance in terms of effective secrecy throughput (EST), and derive its closed-form expression via secrecy outage probability (SOP). We then further investigate the problem of optimal power allocation to maximize overall secrecy performance. The solution to the optimization problem is figured out and demonstrated numerically with an appropriate case.
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.
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.
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.
This paper investigates the secrecy outage performance for a large-scale downlink system with full-duplex (FD) non-orthogonal multiple access (NOMA) transmission aided by artificial noise (AN). In the system, legitimate users (LUs) are randomly distributed according to homogeneous Poisson point processes whereas a passive eavesdropper (Eve) is certainly located. We introduce a secure cooperative communication scheme, in which nearby NOMA users operating in FD mode act as jammers and generate AN to enhance the physical layer security (PLS) of the legitimate transmission. Closed-form expressions in terms of the secrecy outage probability (SOP) for a user pair are acquired. Following the mathematical results, secrecy diversity order analysis is further carried out for two scenarios, i.e., 1) fixed transmit signal-to-noise ratio (SNR) at the Eve, and 2) transmit SNR at the Eve being proportional to that of LUs. Closed-form expressions of asymptotic SOP for the two scenarios are also obtained. Monte Carlo simulations are performed to certify the veracity of the theoretic analysis and illustrate that the proposed scheme employing both AN and FD-NOMA is superior in the secrecy outage to the NOMA scheme without AN and the orthogonal multiple access scheme with AN. Furthermore, the SOP performance enhancement through proper secrecy rate target selection and power allocation optimization is also evidenced by the simulations.
In 5G and beyond wireless communication net-works, non-orthogonal multiple access (NOMA) and Full-Duplex (FD) techniques are considered as promising key techniques. However, the secrecy in NOMA systems has proven to be quite challenging, especially in the presence of multiple eavesdroppers. For this purpose and using the potential of cooperative and FD communication, we investigate the secrecy performance of dual-hop FD Amplify-and-Forward NOMA system. Based on the channel state information of the first hop, partial relay selection (PRS) is performed to determine the best relay. The secrecy outage behaviour of the considered system is studied through deriving closed-form expressions of the secrecy outage probability (SOP) metric for both strong and weak NOMA users under the presence of multiple eavesdroppers in colluding and non-colluding wiretapping scenarios. Numerical results are also provided to verify the derived analytical results.
In non-orthogonal multiple access (NOMA) systems, serving multiple users in shared resource blocks can allow untrusted users to overhear the messages of other users. In this context, we study a network consisting of a base station (BS), a near user and a far user, where the latter attempts to overhear the message of the former. The near user is a full-duplex (FD) node that can also act as a relay. Two operating scenarios are considered: 1) friendly jammer (FJ), where the FD node broadcasts noise for degrading the channel between the BS and the far user, while receiving data from the BS; and 2) friendly jammer relay (FJR), where, in addition to degrading the channel between the BS and the far user, the FD node relays the message of the far user. We investigate the secrecy performance of the network by characterizing the secrecy outage probability (SOP) in both scenarios. We obtain the exact SOP of the FJ case, and an approximation for the SOP of the FJR scenario, both expressed in closed-form. Numerical results confirm the accuracy of the analytical results. For a given BS power budget and power allocation to the users, it is demonstrated that the jamming and relaying powers are prominent factors to make the NOMA-FJR scheme superior to NOMA-FJ, as well as to conventional and cooperative NOMA schemes.