Physical Layer Security in Cognitive Radio Networks

Cognitive radio networks (CRNs) enable dynamic spectrum access by allowing secondary users to exploit underutilised frequency bands while ensuring non-interference with primary users. The inherent broadcast nature of radio channels renders them vulnerable to eavesdropping and jamming, motivating the integration of physical layer security techniques. Unlike traditional cryptographic methods, physical layer strategies exploit channel variability, noise and interference to guarantee confidentiality and robustness against unauthorised listeners. Key approaches include information-theoretic secrecy coding, artificial-noise injection, cooperative jamming and security-oriented beamforming. Energy-constrained devices further benefit from energy harvesting and simultaneous wireless information and power transfer, which can be optimised to strengthen secrecy rates without compromising spectrum efficiency. Advances in machine learning, particularly deep reinforcement learning, have enabled adaptive resource allocation that maximises long-term secrecy performance under realistic conditions of imperfect channel knowledge and mobility. The global significance of this research spans 5G/6G deployments, Internet-of-Things (IoT) applications and vehicular networks, where resilient, low-latency and energy-efficient secure communications are paramount.

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Physical Layer Security in Cognitive Radio Networks publication trend

The graph below shows the total number of articles in physical layer security in cognitive radio networks across all publications each year (not limited to Nature Index journals).

Technical terms

Cognitive Radio Network (CRN): A wireless system in which unlicensed users opportunistically access spectrum while protecting licensed users from harmful interference.

Physical Layer Security: Techniques that exploit channel characteristics, noise and interference to ensure confidentiality without relying solely on encryption.

Secrecy Rate: The maximum transmission rate at which information can be sent securely such that an eavesdropper gains negligible knowledge.

Channel State Information (CSI): Knowledge of channel conditions (e.g. fading, path loss) used to adapt transmission parameters for performance and security.

Eavesdropper: An unauthorised receiver attempting to intercept or decode confidential communications.

References

1. Deep Reinforcement Learning for Physical Layer Security Enhancement in Energy Harvesting Based Cognitive Radio Networks. Sensors (2023).
2. Secrecy Outage Performance of SWIPT Cognitive Radio Network With Imperfect CSI. IEEE Access (2019).
3. Secrecy Performance of Cooperative Cognitive Radio Networks Under Joint Secrecy Outage and Primary User Interference Constraints. IEEE Access (2020).