A survey on Power Allocation in PD-NOMA for 5G Wireless Communication Systems

Non-Orthogonal Multiple Access (NOMA) is a proposed technology for 5G NR (New Radio) networks in the future to increase capacity, user fairness, spectrum efficiency, and mass connectivity. NOMA permits several users to share identical radio resources like time slots, subcarriers, or spreading code simultaneously. Therefore, in designing NOMA the main challenge is to select resource allocation algorithms since user pairing and power allocation go hand in hand. NOMA is a general framework that can be easily blended with several recently proposed 5G multiple access schemes. In this survey paper, the NOMA scheme is discussed and thereby provides an overview of the algorithms designed for optimizing power allocation in the power domain NOMA, considering three different parameters: Max-Min Fairness(MMF), maximizing Sum Rate, and maximizing Energy Efficiency in different radio networks.