Driven by massive connections and exponential growth of data in mobile devices, Non-
orthogonal multiple access (NOMA) has become a candidate access technology to meet the
requirement of Internet of things (IoT) in the future network. The combination of multi-carrier
technology and cooperative communication is an efficient solution to significantly improve
the energy efficiency of NOMA systems. Hence, we consider the energy efficiency (EE)
maximization problem for the multi-carrier cooperative NOMA (MC-C-NOMA) systems with …