Physical layer security for NOMA: limitations, issues, and recommendations

Abstract

More and more attention is being directed towards the Non-Orthogonal Multiple Access (NOMA) technology due to its many advantages such as high data rate, enhanced spectral and energy efficiency, massive connectivity, and low latency. On the other hand, secure data transmission remains a critical challenge in wireless communication systems since wireless channels are, in general, exposed. To increase the robustness of NOMA systems and overcome the issues related to wireless transmission, several Physical Layer Security (PLS) schemes have been recently presented. Unlike conventional security algorithms, this type of solutions exploits the dynamicity of the physical layer to secure data using a single iteration and minimum operations. In this paper, we survey the various NOMA-based PLS schemes in the literature, which target all kinds of security properties. From this study, we have noticed that the majority of the research work in this area is mainly focused on data confidentiality and privacy and not on other security properties such as device and source authentication, key generation, and message integrity. Therefore, we discuss the PLS data confidentiality schemes for NOMA and their limitations, challenges, and countermeasures, and we propose different methods to address the remaining security properties.