Abstract: Focused on the large inter-user interference in Multiple Input Multiple Output-Non-Orthogonal Multiple Access (MIMO-NOMA) technology, an algorithm merging user scheduling and BeamForming (BF) was proposed. Firstly, during the course of user scheduling, in order to simultaneously take intra-cluster user interference and inter-cluster user interference into account, all user groupings were initially sparsely processed by the L1-norm regularization method according to the channel difference among users. In the respect of user channel correlation, two users with large channel correlation were divided into a cluster. Secondly, Fractional Transmit Power Control (FTPC) was used to implement the power allocation of the intra-cluster users. Finally, an objective optimization function based on sum rate maximization criterion was constructed, which was solved by Successive Convex Approximation (SCA) method to obtain the BF matrix. Compared with OMA (Orthogonal Multiple Access), the proposed scheme achieves 84.3% improvement in system capacity, and compared with the traditional correlation user clustering method, it achieves 20.2% improvement in fairness. The theoretical analysis and simulation results show that the proposed scheme not only suppresses the intra-cluster interference and inter-cluster user interference effectively, but also ensures the fairness among users.

Key words: Multiple Input Multiple Output (MIMO), Non-Orthogonal Multiple Access (NOMA), user scheduling, BeamForming (BF), Successive Convex Approximation (SCA)

摘要： 针对多输入多输出—非正交多址接入（MIMO-NOMA）技术中用户间干扰较大的问题，提出了一种融合用户调度的波束赋形（BF）算法。首先，在进行用户调度时，为了同时兼顾簇内用户干扰和簇间用户干扰，根据各用户信道的差异性，利用L1-范数正则化方法对所有用户分组情况进行初步稀疏化处理，进而从各用户信道相关性角度出发，将信道相关性大的两个用户分为一簇；其次，结合部分发射功率控制（FTPC）策略实现簇内用户功率分配；最后，根据和速率最大化准则构建一目标优化函数，进而利用连续凸逼近（SCA）算法对其进行求解，以获得波束赋形矩阵。理论分析和链路仿真表明，与传统的正交多址接入技术相比，在系统容量方面实现了84.3%的提升；与传统的相关性用户分簇方法相比，在公平性方面实现了20.2%的提升。实验结果表明，该方案不仅有效地抑制了簇内用户干扰和簇间用户干扰，同时，又保证了用户间的公平性。

关键词: 多输入多输出, 非正交多址接入, 用户调度, 波束赋形, 连续凸估计逼近