Comparison of Quantization Techniques for Downlink Multi-User MIMO Channels with Limited Feedback

This letter evaluates three quantization techniques for downlink multiple-user multiple-input multiple-output (MU-MIMO) systems with limited feedback. The required feedback bits for a specified rate loss are quantified, as well as the complexity for each technique. Furthermore, the net capacity, which incorporates the effect of the overhead, is studied. The analysis and simulation results reveal the advantages and drawbacks of each quantization method and demonstrate under what conditions to use one of them rather than the other.