Recent Advances and Future Research Challenges in Non-Orthogonal Multiple Access for 5G Networks

Non-orthogonal multiple access (NOMA) has been acknowledged as an emerging technique for multiple access techniques in fifth generation (5G) wireless network. It offers progressive and attractive features such as low latency, ultra-dense coverage, high fairness and new waveform design as compared to the previous schemes. In this paper, recent advances and future research challenges of NOMA is mainly considered. We start by summarizing the existing works with emphasis on recent literature in resource allocation, performance analysis, principal features related to NOMA, and various types of NOMA techniques are discussed. We offer comparative features on demonstrating how NOMA impacts device to device (D2D) communications, cognitive radio networks, massive multiple input multiple output (MIMO), radio frequency (RF) energy harvesting, and other emerging technologies in 5G. Finally, we present the future research challenges and recommendations in order to mitigate the existing issues and advance this unique feature in 5G.