NOMA schemes for 5G green mobile networks
The nonorthogonal multiple access (NOMA) is one of the fledging paradigms that the next generation radio access technologies sprouting toward. The NOMA with superposition coding (SC) in the transmitter and successive interference cancelation (SIC) at the receiver comes with many desirable features and benefits over orthogonal multiple access such as orthogonal frequency division multiple access adopted by long-term evolution. Various studies reveal that the NOMA is a noble spectrum-efficient technique, which can also be designed in the light of energy efficiency. In this chapter, we study the recent progresses of NOMA in fifth-generation (5G) systems. We discuss the basic concepts of NOMA and explain its aspects of importance for future radio access. Then, we provide a survey of the state of the art in NOMA solutions for 5G systems with numerical performances and provide some avenues for future research on NOMA on a set of open issues and challenges.