Practical downlink transmission schemes for future LTE systems with many base-station antennas

We consider downlink multi-user MIMO transmission of a wireless system in which the base station is equipped with a large number of antennas. We propose two downlink schemes based on random beamforming and subspace tracking and show that while reducing signaling overhead, these schemes can improve the system performance compared to conventional systems with a smaller number of antennas at the base station.