Joint User Scheduling and Power Allocation for Weighted Sum-Rate Maximization in NOMA Networks

This paper investigates optimal user selection and power distribution among users for Weighted Sum-Rate Maximization (WSRM) in downlink Non-Orthogonal Multiple Access (NOMA) networks. For a two-user WSRM problem, closed form solution which guarantees successful Successive Interference Cancellation (SIC) decoding is derived. Based on this result, a novel algorithm for joint user selection and power allocation for a multi-user scenario is presented. The proposed algorithm has the following advantages (i) solution exists under all user weigh-tratio scenarios irrespective of the convexity of the optimization problem (ii) successful SIC decoding is guaranteed (ii) has low complexity (iv) provides optimal solution. Extensive simulation results reveal that the optimal result is obtained under different user weight-ratio scenarios.