QoS-based resource allocation for uplink NOMA networks

Nowadays, several next-generation multiple access technologies are proposed, and non-orthogonal multiple access (NOMA) is one of the candidates. In NOMA systems, since the utilization of successive interference cancellation (SIC), the SIC order is one of the significant factors to be considered. In the literature, the SIC order is usually determined by the channel gains, which is not stable especially when the users are with similar channels. In this paper, we creatively propose the quality-of-service-based SIC order in the uplink NOMA system, and focus on the resource allocation to maximize the rate. Specifically, we first optimize the powers with given user grouping and provide solutions for different cases of channel gains. Furthermore, the Hungarian algorithm is jointly exploited with the optimized powers. Simulation results show that the proposed algorithm outperforms traditional orthogonal multiple access and even achieves similar rate with the exhaustive search.