Enhanced Beamforming Over Multiple Iterations for Downlink Broadcast Channels
In this paper, the authors investigate efficient beam-forming schemes for downlink broadcast channels of MIMO systems. Optimal solution to this problem is known to be infeasible due to the prohibitive complexity and recent research focuses on suboptimal approaches with reduced complexity. They first present a progressive beam-forming method that maximizes the net gain in sum throughput for newly added users and achieves high sum throughput in MU-MIMO channels. Nevertheless, there is severe asymmetry in the performance between data streams: data streams scheduled at an earlier stage are better protected compared to their counterparts configured in later stages.