Subcarrier Allocation for Rate Maximization in Multiuser OFDM NOMA Systems on Downlink Beamforming

In this paper, we present resource allocation algorithms to maximize system capacity for multicarrier nonorthogonal multiple access (MC-NOMA) systems on downlink beamforming. The proposed solution has two steps. First, a user pairing algorithm is applied, and then a subcarrier allocation scheme is proposed to maximize sum capacity. In this system under consideration, each subcarrier can be assigned to two users per antenna beam for transmitting data. After performing the user pairing algorithm, the subcarrier allocation process is performed where a subset of subcarriers is assigned to the cluster which includes groups of users for data delivery. Each group have two users, which are a strong user (SU) and a weak user (WU) and the data steam is transmit to one group per one antenna beam. The simulation results illustrate that the proposed system outperforms the OFDMA system.