Coordinated multi-cell beamforming for TD-LTE-advanced systems

LTE-Advanced systems are built upon the orthogonal frequency division multiple access (OFDMA) technology, which can effectively eliminate the intra-cell interferences, but cannot automatically mitigate the inter-cell interferences (ICI). Coordinated multi-point transmission/reception (CoMP) is one of the candidate enhancement techniques for LTE-Advanced systems to increase both the average and the cell-edge user throughputs in uplink as well as downlink transmissions by jointly managing the inter-cell interferences. Although CoMP may incur more system complexity, it potentially could lead to significant capacity and coverage benefits, which makes it worth more detailed investigation. In this paper, we focus on downlink multi-point coordinated beamforming (CoMP-CBF), and study a particular multi-stream beamforming scheme. We also present detailed system level performance evaluation of the proposed scheme against a reference LTE Rel.8 non-cooperative scheme, which shows that CoMP-CBF transmission could achieve significant gains on both the average and the cell-edge user throughputs.