QoE-aware power control and user grouping in Cognitive Radio OFDM–NOMA systems

As a dramatic advancement in mobile communications, 5G has put together several state of the art technologies including Cognitive Radio (CR) and Quality-of-Experience (QoE). While CR is to overcome frequency scarcity, how to maintain QoE for all the connected users is one of the paramount issues in such integration, especially for multimedia communications. As a key technology for 5G, Non-Orthogonal-Multiple Access (NOMA) is combined with Orthogonal Frequency Division Multiplexing (OFDM) to improve the spectral efficiency. In this paper, the QoE requirements for typical applications in a CR platform are characterized, based on which a method for user grouping and power management in an OFDM–NOMA system is proposed. The performance of the proposed method is analyzed and evaluated by simulating a typical network. The evaluations show noticeable improvement in transmit power reduction while the requested users’ perception levels are maintained.