An efficient hybrid transmission method: using nonorthogonal multiple access and multiuser diversity

Nonorthogonal multiple access (NOMA) and multiuser diversity (MUD) are different transmission techniques that can improve the spectral efficiency of multiuser wireless communication systems. In this paper, we consider a hybrid switching strategy of NOMA and MUD (HSS-NM) by combining these two approaches in two-user and multiuser systems. With NOMA using successive interference cancellation and MUD based on proportional fair scheduling, we find out that one can perform better than the other according to certain channel conditions. From this, HSS-NM is proposed to improve spectral efficiency. Furthermore, we extend HSS-NM to a multiuser scenario with a user selection strategy. Simulation results demonstrate that the proposed method can achieve a relatively high sum-rate gain.