A novel tree-based scheduling algorithm for the downlink of multi-user MIMO systems with ZF beamforming

Spatial multiplexing in the downlink of wireless multiple antenna communications promises high gains in system throughput. However, spatially correlated users and a limited number of antennas at the base station motivates the need for a scheduling algorithm which efficiently arranges users into groups to be served in different time or frequency slots. In this paper we propose a novel tree-based scheduling algorithm which successfully solves this problem achieving a close to optimum grouping strategy. The algorithm has been tested with zero forcing beamforming techniques and is based on a new metric for the user performance considering the effect of other users present in the same group analyzing their spatial features.