MUBFP: Multi-user beamforming and partitioning in downlink MIMO systems

Multi-user beamforming (MUBF) scheme has been studied extensively as a linear precoding technique to achieve better performance of system capacity in downlink MIMO systems. Due to mutual interference between users, the objective of maximizing average sum capacity and fair service provisioning to different users should be well balanced in the framework of designing MUBF scheme. To this end, we consider the problem of joint optimization of multi-user beamforming and partitioning (MUBFP), which attempts to find the optimal partitioning of users and their corresponding beamforming weight vectors such that the average sum capacity is maximized. A decomposition approach is developed to decouple this problem into the user partitioning and beamformer design subproblems, which are solved using the agglomerative hierarchical clustering algorithm and sequential parametric convex approximation approach, respectively. An iterative algorithm is proposed to search the optimal partitioning number by incorporating the results of these two subproblems. Simulation results are provided to show the effectiveness of the proposed MUBFP scheme.