An overview of methods to combat eavesdropping in NOMA-based networks through physical layer security

Abstract

Thanks to their potentials in providing reliable communications for a large number of devices, 5G non-orthogonal multiple access (NOMA) techniques have recently been the subject of considerable research interest. Accordingly, research of Physical Layer Security approaches in NOMA is essential. A primary purpose and challenge for security at the physical level of NOMA-based systems is to protect the information transmitted against both external and internal eavesdropping attacks. To this end, it is necessary to develop PLS schemes which allow each user to decode the signals transmitted by other users, thus guaranteeing normal operation of the successive interference cancellation, while also providing privacy of the information exchange. In this paper, different types of eavesdropping are studied and a summary of existing approaches to improve security at the physical layer in 5G NOMA networks is provided.