基于非正交多址接入系统的多用户分组优化算法

用户分组算法作为非正交多址接入(NOMA)的关键部分，对系统吞吐量和用户公平性具有重要影响。当用户数量和可用的资源增加时，用户分组的最佳调度将变得不可行，该文提出一种子带间多用户分组优化算法。该算法首先根据用户信道增益差异和子带复用用户数限制条件进行多用户初始分组处理，减小用户搜索空间，然后逐步完成初始分组用户间的优化组合，以几何平均用户吞吐量最大为用户分组准则，进一步提升小区边缘用户的吞吐量。仿真结果表明，所提算法与传统的用户分组算法相比，系统总吞吐量和几何平均用户吞吐量性能提升均超过3%。

Multi-user Grouping Optimization Algorithm Based on Non-orthogonal Multiple Access Systems

As a key part in Non-Orthogonal Multiple Access (NOMA), user grouping is of particular importance for non-orthogonal multiple access system to improve throughput performance and user fairness. When the number of users and the available resources is increased, the optimal scheduling of user grouping will be infeasible, so a multi-user grouping optimization algorithm for different sub-bands is proposed. According to the user channel gain difference and the restrictions of the multiplexed user number in the same subband, the proposed algorithm firstly performs the process of the initial multi-user grouping to reduce the user’s search space. Then, the optimized combination of the initial grouping users is gradually completed, and the maximum geometric mean user throughput is used as user grouping criterion, which can further enhance the cell-edge user throughput. Simulation results show that the system total throughput and geometric mean user throughput performance of the proposed algorithm can be improved by more than 3% compared with the traditional user grouping algorithms.