A Proposal of DPC Beamforming for Open Loop Multiuser MIMO Transmissions

This paper proposes an open loop beamforming scheme in frequency division duplex (FDD) downlink multiuser multiple input multiple output (MIMO) transmissions. The proposed scheme estimates the downlink channel matrix by uplink direction of arrival (DOA) estimation, and generates the beamforming weight such that the effect of overlapping beams is cancelled at the respective receivers by applying the dirty paper coding principle. The simulation results show that the proposed scheme provides a gain up to 20 dB in the received signal to noise plus interference ratio (SINR) at the 50 % CDF compared to the conventional zero-forcing beamforming. In addition, it is shown that the proposed scheme has a superior performance to the limited feedback closed loop scheme.