User Selection and Power Allocation for Guaranteed SIC Detection in Downlink Beamforming Non-Orthogonal Multiple Access

Non-Orthogonal Multiple Access (NOMA) is a promising multiple access technique for the 5th generation (5G) mobile communication systems. In this paper, an efficient power allocation scheme is derived for multiuser multiple input single output (MISO) downlink beamforming NOMA system to guarantee that successive interference cancellation (SIC) detection can remove completely the intra-cluster interference. In addition, a fairness-oriented user selection (NOMA-FOUS) algorithm is proposed to maximize the NOMA system sum rate and achieve high system fairness by selecting the two clustered users based on their NOMA data rate. Numerical results show that NOMA-FOUS algorithm provides better system sum rate, weak users sum rate and fairness index performance than that of the other user clustering algorithms with a little increased computational complexity.