Coordinated beamforming in downlink CoMP transmission system

Coordinated multi-point transmission/reception (CoMP) technique for 3GPP LTE-Advanced is to reduce the inter-cell interference (ICI) effectively, so as to enhance data rate/coverage and throughput for cell-edge users significantly. For downlink CoMP, most research work mainly focuses on joint processing/transmission (CoMP-JP) mode. However this mode needs the access points (AP) to share the UEs' data and channel state information (CSI) simultaneously, resulting in a high overhead on the network. Coordinated beamforming (CoMP-CBF), which can avoid the data information exchange is a better solution to reduce the overhead. In this paper, we propose a coordinated beamforming scheme in downlink CoMP transmission system. The proposed scheme exploits the signal leakage information to other cells to design the precoding vector to reduce the ICI. The simulation results indicate that the proposed scheme offers much higher performance gain compared with the CoMP-JP mode.