Resource Allocation Ensuring Physical Layer Security in Cooperative Non-Orthogonal Multiple Access in 6G Networks

Non-Orthogonal Multiple Access (NOMA) is a potential candidate for 6th Generation (6G) cellular communication. It outperforms the conventional Orthogonal Multiple Access (OMA) schemes in terms of connectivity, spectral efficiency and latency. In spite of these advantages, NOMA faces information security challenges. In this paper, two phases of NOMA are considered which are the direct transmission phase and the cooperative phase. In the direct transmission phase, all users receive the superimposed signal while in the cooperative phase the user with a higher channel condition helps the user with the weaker channel condition. In the proposed work, the secrecy rate of users with weaker channel conditions is considered for maximisation under total power and Quality-of-Service (QoS) constraints. Our results show an improvement in the secrecy rate.