Multi-sector joint beamforming for 3D coverage control of common control signals

With the emergence of large high-rise buildings and three-dimensional (3D) space distribution of wireless traffics, there exists a new demand of forming seamless high-quality coverage of the common control signals in cellular mobile communication networks. In this paper, 3D coverage control mechanism based on beamforming using planer array antenna of base station (BS) is explored. A novel multi-sector joint control approach is proposed, in which the control is conducted for a sector cluster consisting of several sectors and is according to the heterogeneous coverage requirements and propagation conditions. It jointly utilizes the freedom degrees of beamforming of multiple BS antennas, and cooperatively forms the desired 3D coverage for the whole sector cluster. The optimization model is established to find the excitation weights of the BSs' planer array antennas so that the approximately average Signal-to-Interference Ratio (SIR) is maximized under the constraint of no weak coverage. The antenna excitation weights are obtained through iteration. As compared with the baseline which controls each sector/cell's coverage individually, the proposed algorithm has been validated by using numerical results to have the advantages of eliminating weak coverage and improving SIR.