On the physical layer security performance of full‐duplex cooperative NOMA system with multiple eavesdroppers, imperfect SIC and hardware imperfections
Abstract In this letter, we propose a control jammer‐assisted framework for improving the physical layer security (PLS) of full‐duplex (FD) ‐ cooperative non‐orthogonal multiple access (FD‐CNOMA) network. We derive analytical expressions for the secrecy outage probabilities (SOPs) of the users for the jammer‐assisted and the no‐jammer scenarios, considering multiple non‐colluding eavesdroppers, residual hardware impairments and imperfect successive interference cancellation conditions. It is demonstrated that the proposed jammer‐assisted framework provides significant reduction of the SOPs experienced by the downlink users in FD‐CNOMA network.
Abstract In this letter, we propose a control jammer‐assisted framework for improving the physical layer security (PLS) of full‐duplex (FD) ‐ cooperative non‐orthogonal multiple access (FD‐CNOMA) network. We derive analytical expressions for the secrecy outage probabilities (SOPs) of the users for the jammer‐assisted and the no‐jammer scenarios, considering multiple non‐colluding eavesdroppers, residual hardware impairments and imperfect successive interference cancellation conditions. It is demonstrated that the proposed jammer‐assisted framework provides significant reduction of the SOPs experienced by the downlink users in FD‐CNOMA network.
This article explores various approaches to enhance the physical layer security performance of cooperative non-orthogonal multiple access (CNOMA) system, in scenarios involving multiple non-colluding or colluding eavesdroppers, taking into account residual hardware impairment (RHI) and imperfect successive interference cancellation conditions. Firstly, we propose a jamming-assisted (JA) framework for enhancing the physical layer security performance and derive analytical expressions for the secrecy outage probabilities (SOPs) of the downlink users and the system SOP (SSOP) of the CNOMA network for both JA and no-jammer (NJ) scenarios. It is illustrated that the proposed JA framework offers several key benefits: (i) a significant reduction in the SOPs and SSOP, (ii) a notable increase in system secrecy throughput (SST) and secrecy energy efficiency (SEE) for the network, and (iii) a complete alleviation of the zero-diversity order problem, if the transceivers are free of RHI. Following this, the optimal power allocation coefficients for the users at the base station and at the relay that independently as well as jointly minimize the SSOP of the JA-CNOMA network are determined. We demonstrate that the proposed approach results in: (i) considerable decrease of SSOP and SOPs and (ii) significant enhancement of SST and SEE of the JA-CNOMA network, compared to equal/random power allocation methods.
Abstract In this paper, we analyze the physical layer security (PLS) performance of nonorthogonal multiple access (NOMA)‐enabled overlay cognitive radio networks (NOMA‐OCRNs) in the presence of an external passive eavesdropper. Here PLS is expressed in terms of the secrecy outage probabilities (SOPs) experienced by the primary user (PU) and secondary user (SU). We obtain approximate expressions for the SOPs of both PU as well as SU assuming a jamming‐free environment, where both primary and secondary destination nodes are half‐duplex devices. To improve the SOP performance, we propose a jamming‐assisted framework, where full‐duplex destination nodes are employed, which are capable of transmitting jamming signals to confound the eavesdropper. Approximate expressions for the SOPs of PU and SU are derived for the jamming‐assisted framework as well. It is demonstrated that the proposed jamming‐assisted framework significantly reduces the SOPs compared to the jamming‐free scenario. We also determine optimal power allocation coefficients (OPACs) for PU and SU at the secondary transmitter that maximizes the total secrecy throughput of the jamming‐assisted NOMA‐OCRN with FD destinations. It is shown that the suggested OPAC significantly enhances the total secrecy throughput, compared to the default selection of the PAC.
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.
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.
The issues of the physical layer security are studied, where one transmitter (Alice), one full‐duplex (FD) legitimate receiver (Bob) and one multi‐antenna jammer (Charlie) are considered to defend against multiple passive and non‐colluding eavesdroppers (Eves), for multiple‐input multiple‐output wiretap channels. With the assumption that the complete channel state information (CSI) for main channels and the statistical CSI for Eves' channels are available, an improved secrecy transmission design is proposed to minimise the secrecy outage probability (SOP), under the minimum secrecy rate requirement. In addition to integrating artificial noise aided transmit beamforming and multi‐antenna cooperative jammer to impair Eves' channels, which is widely used in many existing works, a FD legitimate receiver is applied together to further enhance physical layer security. Based on the basic probability theory and convex optimisation, the accurate closed‐form expression of the SOP is derived, and the impacts on secrecy performance are described, including the qualities of main channels, the Alice's transmit power and the number of Eves. Numerical results show that the proposed scheme using the FD Bob can significantly enhance the system security, as compared with that employing the half‐duplex Bob.
Abstract Cooperative Non‐orthogonal Multiple Access (C‐NOMA) is projected as the dominant technology for 5G and beyond. Also, physical layer security, due to the presence of eaves‐dropper, is a bottleneck security concern for any open link wireless system. This manuscript presents a novel Decode & Forward (DF)‐based C‐NOMA system in the presence of two eavesdroppers. Moreover, both half duplex and full duplex schemes are included in the analysis. Thereby, separate expressions for Secrecy Outage Probability (SOP), being among the most crucial performance measures in physical layer security, are produced and examined for the system under consideration. Specifically, first of all, novel expression of SOP for C‐NOMA systems under both Half Duplex (HD) and Full Duplex (FD) schemes is derived for the case when only eavesdropper one (E1) attacks on link source to device one (S‐D1). Thereafter, expressions of SOP for the C‐NOMA system under both HD and FD schemes are derived, considering presence of E1 and E2 on the links, source to device one (S‐D1) and source to device two (S‐D2), respectively. Further, for both the duplexes, the effect of eavesdropper one (E1) and eavesdropper two (E2) on the links, S‐D1 and S‐D2, respectively, is analyzed. The presented analysis is useful in the technological development level of C‐NOMA in the presence of multiple eavesdroppers. The simulated results show perfect agreement with the theory.