A Novel Low Complexity Power Allocation Algorithm for Downlink NOMA Networks

This paper investigates optimal power distribution which guarantees Quality of Service (QoS) for Weighted Sum-Rate Maximization (WSRM) in downlink Non-Orthogonal Multiple Access (NOMA) networks. For a two-user WSRM problem, closed form solution is derived. Based on this result, a novel power allocation algorithm for a multi-user scenario is presented in this paper. The proposed algorithm has the following advantages: solution exists under all user weight-ratio scenarios irrespective of the convexity of the optimization problem; successful Successive Interference Cancellation (SIC) decoding is guaranteed; has low complexity; provides optimal solution. Extensive simulation results are provided to evaluate the performance of the proposed algorithm under different user weight-ratio scenarios.