Physical layer security for NOMA: requirements, merits, challenges, and recommendations

Abstract

Non-orthogonal multiple access (NOMA) has been recognized as one of the most significant enabling technologies for future wireless systems due to its eminent spectral efficiency, its ability to provide an additional degree of freedom for ultra reliable low latency communications (URLLC), and grant free random access. Meanwhile, physical layer security (PLS) has got much attention for future wireless communication systems due to its capability to efficiently complement the cryptography-based algorithms for enhancing overall security of the communication system. In this article, security design requirements for downlink power domain NOMA and solutions provided by PLS to fulfil these requirements are discussed. The merits and challenges which were encountered while employing PLS to NOMA are identified. Finally, future recommendations and prospective so lutions are also presented.