Three-dimensional coverage control of common control signals for cellular networks

Rapid increase of large-scale high-rise structures results in three-dimensional distribution of wireless traffic, and thus raises a new demand of three-dimensional coverage of the common control signals in cellular mobile communication networks. The control approach of three-dimensional coverage is investigated in this paper, based on planar array of macro basestation and three-dimensional beamforming technology. A novel algorithm is proposed for obtaining the excitation weight matrix of planar array. Coverage requirement is extracted according to the target coverage distances and the actual landforms in different directions, and then mapped into an anisotropic desired array pattern. The optimization model is established as a joint minimization of array pattern design error and transmission power. An approximately optimal tradeoff coefficient and the corresponding weight matrix are solved through iteration. Numerical results validate that the proposed algorithm has the advantages of excellent coverage performance, considerable saving of transmission power and effective suppression of inter-cell interference.