2011 Volume E94.A Issue 12 Pages 2719-2727
This paper proposes an open loop beamforming scheme for downlink multiuser multiple-input multiple-output (MIMO) transmissions in frequency division duplex (FDD). The proposed scheme uses the uplink direction of arrival (DOA) estimation, and then generates the beamforming weight such that the interference caused by the overlapping beams is removed by applying the dirty-paper coding (DPC) principle. The simulation results show that the proposed scheme provides the gain of 32.3% at minimum in terms of the spectral efficiency at the CDF of 50% compared to the conventional DOA based beamforming scheme. In addition, it is shown that the proposed scheme has superior performance to closed loop scheme with the limited feedback information.