Interference Suppression Based Beamforming Scheme for LTE Downlink MIMO

In LTE downlink multiple-input multiple-output (MIMO), eigen based beamforming (EBB) is a promising approach for single-user scenario, while block diagonalization based beamforming (BDBF) eliminates intra-cell interferences significantly for multi-user scenario. However, both of them neglect inter-cell interferences which may lead system performance degradation. This paper presents an interference suppression based beamforming (ISBF) scheme to suppress inter-cell interferences. We first introduce interference suppression matrix (ISM) into EBB and BDBF to propose a novel beamforming matrix construction method. Then the ISM reporting scheme is discussed to support ISBF, and a precoded uplink pilot based (PUPB) reporting scheme is presented exploiting the channel reciprocity in TDD system. Finally, the simulation results are provided using dynamic system level simulator. Our results show that ISBF improves cell average and cell edge spectral efficiency significantly compared with traditional EBB and BDBF.