# Advanced Security Framework for 6G Networks: Integrating Deep Learning and Physical Layer Security
###### Abstract
PLS techniques, such as channel quantisation and precoder matrix indexing (PMI), depend on the inherent differences in the communication channel rather than the signal-to-noise ratio (SNR), making them resilient to eavesdropping, even when the eavesdropper is physically closer to the transmitter [21, 22]. However, despite its advantages, PLS is not immune to various security attacks that target the transmission channel [23, 24]. Common attacks include spoofing, jamming, and eavesdropping. Spoofing attacks involve an adversary impersonating a legitimate user by altering the transmitted signals, potentially gaining unauthorised access to sensitive information or network resources. Jamming attacks, on the other hand, involve deliberate interference with the communication channel by emitting disruptive signals, thereby degrading the quality of service or even causing complete denial of service. Eavesdropping remains a significant threat, where an attacker intercepts the communication between legitimate users to gain access to confidential information without altering the transmission. These attacks exploit the vulnerabilities at the physical layer, necessitating robust countermeasures within PLS frameworks to ensure secure and reliable communication. Advanced PLS techniques, such as utilising unique channel state information and adaptive modulation schemes, are essential to mitigate these threats and enhance the overall security of next-generation wireless networks [25]. Although PLS leverages the inherent properties of wireless channels, such as noise, fading, and interference to protect transmitted information from unauthorised access without relying solely on traditional cryptographic methods, a growing area of research, known as covert communications, extends beyond PLS by focusing on ensuring the very existence of the transmission remains undetected. This makes covert communications a highly relevant technique for environments where merely being noticed could compromise operations. Covert communications, also known as low probability of detection communications, are designed to conceal the transmission, not just the content of the information being sent. It is this that can make all the difference in applications where a lack of detection may be at least as important as data confidentiality in surveillance and other sensitive operations. While PLS offers security via the undecidability of information by unauthorised parties, in covert communication, even the detection of a transmission by adversaries should not be allowed. This additional layer of security becomes crucial in wireless systems where adversaries can easily monitor the communication environment. The integration of covert communication with PLS offers a robust solution for next-generation networks, including 6G. The authors in [26] explore this methodology by examining how covert communications can be integrated with energy-harvesting techniques. In their work, the authors propose a system where nodes harvest energy from the environment and opportunistically relay covert signals, ensuring that the transmission remains undetected while still maintaining efficient communication. Their findings show that this combined approach not only improves energy efficiency but also strengthens the covertness of transmissions, making it particularly useful for low-power devices such as IoT sensors and UAVs. The research group in [27] investigate how covert communications can be applied to mobile systems such as UAVs. The study presents a twin delayed deep deterministic policy gradient (TD3) and prioritised experience replay (PER) solution to optimise UAV flight paths, ensuring that their transmissions are both efficient and undetectable. The dynamic nature of the trajectory design allows the UAV to adapt its movement based on environmental factors and potential adversarial detection. Several other studies support the importance of covert communications in enhancing transmission security.