The Non-Orthogonal Multiple Access (NOMA) and Reconfigurable Intelligent Surface (RIS) technologies enhance spectral efficiency by permitting multiple users to share similar resources. However, resource sharing can introduce security risks in NOMA systems with internal users. Security-enhancing techniques for NOMA with eavesdroppers have been proposed to address these concerns. One such approach is the Artificial Noise- Beamforming and Power Allocation (ABPA) methodology, which incorporates noise and power management to enhance security. Additionally, using a reflecting surface and channel fuzziness enables the extraction of a secret key for reliable encrypted data transmission while also introducing intentional interference and confusing potential eavesdroppers. The intelligent control of reflections by the RIS further enhances security by creating complex interference patterns that are challenging to decipher. These frameworks provide promising solutions for mitigating the risks posed by internal eavesdroppers in NOMA systems, leveraging advanced signal manipulation techniques.
The Non-Orthogonal Multiple Access (NOMA) and Reconfigurable Intelligent Surface (RIS) technologies enhance spectral efficiency by permitting multiple users to share similar resources. However, resource sharing can introduce security risks in NOMA systems with internal users. Security-enhancing techniques for NOMA with eavesdroppers have been proposed to address these concerns. One such approach is the Artificial Noise- Beamforming and Power Allocation (ABPA) methodology, which incorporates noise and power management to enhance security. Additionally, using a reflecting surface and channel fuzziness enables the extraction of a secret key for reliable encrypted data transmission while also introducing intentional interference and confusing potential eavesdroppers. The intelligent control of reflections by the RIS further enhances security by creating complex interference patterns that are challenging to decipher. These frameworks provide promising solutions for mitigating the risks posed by internal eavesdroppers in NOMA systems, leveraging advanced signal manipulation techniques.
The reconfigurable intelligent surface (RIS) aided non-orthogonal multiple access (NOMA) network is applied to improve spectral efficiency and energy efficiency of wireless systems. Due to the incorporation of NOMA, RIS-aided NOMA system suffers from physical layer security (PLS) problem when an internal near user (NU) is the eavesdropper. In this case, it is difficult to always guarantee positive secrecy rate. Therefore, a scheme of artificial noise (AN) cooperative jamming and beamforming design is proposed against internal eavesdropper for RIS-aided NOMA in this paper. It is proved theoretically that the positive secrecy rate can be guaranteed if providing sufficient power. In addition, the power allocation of base station is further studied to minimize the total power consumption under the constraints of data rate and secrecy rate, and the closed-form solutions are achieved. Simulation results show that the performance of the proposed scheme is superior to the existing solutions.
The key idea of non-orthogonal multiple access (NOMA) is to serve multiple users in the same resource block to improve the spectral efficiency. Whereas due to the resource sharing, a security flaw of NOMA emerges in the presence of internal untrusted users, especially untrusted near users who are closer to the base station and can easily access the confidential information for paired far users. To mitigate the flaw, in this paper, we investigate the reliable and secure transmission of NOMA systems with untrusted near users, and propose joint beamforming and power allocation (JBP) scheme for the scenario. Meanwhile, from security point of view, we extend to a worse-case scenario where both untrusted near users and external eavesdroppers exist, and propose joint artificial noise aided beamforming and power allocation (JANBP) scheme to achieve a reliable and secure transmission for the scenario. The exact and asymptotic closed-form expressions of secrecy outage probability (SOP) for the two scenarios are derived to evaluate the secrecy performance achieved by the proposed schemes, respectively. The analysis and simulation results show the superiority of the proposed JBP and JANBP schemes in terms of combating internal and external eavesdropping, and also indicate the two schemes can achieve the same SOP at high SNR.
Non-orthogonal multiple access (NOMA) is an efficient approach that can improve spectrum utilization and support massive connectivity for next-generation wireless networks. However, over a wireless channel, the superimposed NOMA signals are highly susceptible to eavesdropping, potentially leading to severe leakage of confidential information. In this article, we unleash the potential of network interference and exploit it constructively to enhance physi-cal-layer security in NOMA networks. In particular, three different types of network interference, including artificial noise, specifically-designed jamming signals, and inter-user interference, are well engineered to intentionally reduce information leakage while mitigating the effect on signal reception quality of legitimate users, thereby significantly enhancing the transmission security of NOMA. Furthermore, we propose interference engineering strategies for more advanced full-duplex NOMA, intelligent reflecting surface NOMA, cognitive radio NOMA, and multi-cell NOMA networks, and discuss several open research problems and challenges, which could inspire innovative interference engineering designs for secure NOMA communications.
This letter investigates the physical layer security of a downlink non-orthogonal multiple access (NOMA) system aided by a reconfigurable intelligent surface (RIS), where artificial noise (AN) is introduced to confuse the eavesdropper. To enhance secrecy, we employ improper Gaussian signaling (IGS) to alleviate the influence of AN on legitimate users. This is formulated as a sum secrecy rate maximization problem, where the reflecting coefficients of RIS and transmit covariance matrices of legitimate users and eavesdroppers are jointly optimized. An alternating optimization framework aided by the minorization-maximization method is adopted to address this non-convex optimization problem. Numerical results show that IGS significantly outperforms proper Gaussian signaling in improving the secrecy performance of RIS-aided NOMA systems, and such a secrecy advantage is more pronounced in RIS-aided NOMA than in traditional NOMA.
Abstract With the exponential growth of wireless communication technologies, ensuring the confidentiality of transmitted data has become paramount. This paper introduces a cutting-edge encryption scheme utilizing Non-Orthogonal Multiple Access (NOMA) for secure key generation. It proposes a method that utilizes an identical secret key derived from channel randomness and distance to prevent eavesdropping in NOMA communication, thus enhancing the system's resistance against potential attacks. NOMA is employed to simultaneously serve multiple users at the same time and frequency resources by applying different power levels to each user. In the proposed encryption scheme, NOMA principles combine channel randomness and user-base station distance in a non-orthogonal manner. This approach allows the generation of identical encryption keys shared by multiple users, ensuring an efficient and robust security mechanism benefits increased spectral efficiency and an improved system. The non-orthogonal of the generated encryption key enhances the security level, as it becomes harder for eavesdroppers to intercept and decipher the key. Integrating NOMA in the key generation process introduces an additional layer of unpredictability, further bolstering security. Extensive simulations and analyses were conducted to assess the proposed NOMA-based dual key extraction performance. A qualitative comparison between sources and a new proposed direction shows the Secrecy rate, key secrecy capacity, and secrecy outage probability demonstrate its effectiveness in providing a high level of security while incurring minimal overhead on the communication system.
Non-orthogonal multiple access (NOMA) is emerging as a popular radio access technique to serve multiple users under the same resource block to improve spectral efficiency in 5G and 6G communication. But the resource sharing in NOMA causes concerns on data security. Since power domain NOMA exploits the difference in channel properties for bandwidth-efficient communication, it is feasible to ensure data confidentiality in NOMA communication through physical layer security techniques. In this work, we propose to ensure resistance against internal eavesdropping in NOMA communication through a secret key derived from channel randomness. A unique secret key is derived from the channel of each NOMA user; which is used to randomize the data of the respective user before superposition coding (SC) to prevent internal eavesdropping. The simulation results show that the proposed system provides very good security against internal eavesdropping in NOMA.