On the Performance of Adaptive Limited Feedback Beamforming in Distributed MIMO Systems

This paper analyzes the performance of limited feedback (LFB) beamforming in multiple-input multiple-output (MIMO) distributed antenna systems (DAS). The averaged effective signal-to-noise ratio (ESNR) is derived for both the case where all antenna ports are used for transmission (blanket transmission, BT) and the case where only one of the ports are selected (port selection, PS). Based on the derived ESNR, we propose two adaptive LFB beamforming schemes for MIMO DAS, which switch between BT and different PS schemes. Through simulations, we confirm the analytical studies and investigate the performance of different LFB beamforming schemes.