3D-MIMO Beamforming For Wireless Communication Systems With Large-scale Antenna Array

With the advent of the Active Antenna System(AAS),the Three Dimension Multiple-Input Multiple-Output(3D-MIMO)technology has been considered as one of the key technologies for the fifth generation mobile communication system(5G).3D-MIMO beamforming implements not only the horizontal dimensional but also the vertical dimensional beamforming control.In a multi-user wireless communication system downlink,multiple users share the same time-frequency resource,which inevitably leads to co-channel interference(CCI)between the activated users.Due to the independence among the co-channel users,it is hard for them to communicate with each other cooperatively.Therefore,an effective 3D-MIMO beamforming technology is necessary to adjust the direction of the transmit beam,and the transmit beam can be more accurately pointed to the target user in the actual three-dimensional space.Accordingly,the suppression of co-channel user interference can be achieved,and the system performance is improved.In this paper,the non-codebook-based 3D-MIMO multiuser beamforming and the codebook-based 3D-MIMO multiuser beamforming are studied for wireless communication systems using large-scale antenna arrays.For the codebook-based 3D-MIMO multiuser beamforming scheme,an improved 3D codebook design scheme is proposed.Assuming an Uniform Plane Array(UPA)equipped at the base station,in our scheme,the vertical dimension codebook design is given based on spatial non-uniform segmentation and space-based uniform segmentation separately.And the initial phase of the horizontal dimension codebook is appropriately adjusted.Then a new 3D beamforming codebook is constructed based on the Kronecker product of the horizontal dimension codebook and the vertical dimension codebook.The improved 3D beamforming codebook maximizes the distance between codewords and more fully utilizes the horizontal and vertical dimensional information of the communication system.Simulation results show that,compared with the 3D codebook based on spatially non-uniform segmentation and the 3D codebook based on spatially uniform segmentation,the improved 3D codebook presented in this paper can effectively suppress the co-channel interference between users and improve the system spectrum utilization,so that the system performance can be improved effectively.