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.
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.
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) has been regarded as a key enabling technology for sixth-generation (6G) communications, since resource utilization was significantly enhanced by allowing multiple users to share the same time-frequency and spatial resources. However, in power-domain NOMA systems, user privacy information may be eavesdropped due to the application of successive interference cancellation, which introduces potential security vulnerabilities. To address this issue, various physical layer security schemes have been proposed in the literature, while their performance was highly dependent on sufficiently accurate channel state information (CSI). When channel estimation accuracy was insufficient, the achievable security performance often failed to meet expectations. To overcome this limitation, a physical layer security scheme based on channel estimation error compensation was proposed under imperfect CSI conditions. First, channel estimation errors were compensated through an additional low-complexity estimation process. Then, the transceiver was redesigned based on the more accurate CSI obtained after error compensation. Simulation results demonstrated that the proposed scheme significantly improved the secrecy rate and transmission reliability under different levels of channel estimation errors and signal-to-noise ratio. This scheme now provides a feasible solution to the physical layer security problem in scenarios where channel estimation errors exist.
The close relationship between multiple access technologies and efficient spectrum utilization makes power- domain non-orthogonal multiple access (NOMA) an attractive solution that enables the support of high data rates, user fairness and low-latency communications in 5G and next generation networks. However, user pairing and successive interference cancelation applied in NOMA facilitates eavesdropping on the far user’s signal by the near user establishing security as a main issue in NOMA systems. Due to their numerous advantages, the means of physical layer security (PLS) are extremely suitable to combat internal NOMA eavesdropping. Up to the present only a few studies exist which examine different PLS approaches against eavesdropping on the far user by the near user. Among them are a joint beamforming and power allocation algorithm, an angle conversion method that alters the original signal constellation before transmission, and a directional modulation approach. In this paper, the available PLS methods against eavesdropping on the far user by the near user are investigated and the main advantages and drawbacks of these methods are compared.
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.
Enhancing security level against potential internal eavesdroppers in Non-Orthogonal Multiple Access (NOMA) has been reported as a serious challenge. In this letter, a novel secure NOMA scheme based on physical-layer security concepts is proposed. The proposed scheme exploits the random and independent channel characteristics to induce a different phase shift in each user's symbol. Based on the assumption that the instantaneous channel phase between a user and the base station is available only at both ends, other users will not be able to decode the right symbol. Analytical and simulation average bit error rate performance results demonstrate the ability of the proposed scheme to degrade the performance at the eavesdropper without affecting the performance at other legitimate users and guarantee data confidentiality of each user.
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.