Research Of Beamforming Technology In 3D MIMO

As the important direction of LTE-Advanced multi-antenna technology and one of the key technology in 5G communication,3D MIMO obtain multitudinous scholar's widespread attention and thorough research.Traditional MIMO array antenna can only be used to change the main lobe point of desired direction through using the horizontal dimension information,however,under 3D MIMO scene,two freedom degrees of horizontal and vertical dimension are used by antennas array to make the main beam point be more accurate and flexible.Along with the growing demand of communications capacity and network traffic,an effective method for solving the problem of urban high-rise buildings network cover and square scene collective flux demand,and a new processing method for improving the community communication rate are provided by 3D MIMO beamforming technology.The Capon beamforming algorithm is studied deeply based on MIMO communication mechanism and general beamforming algorithm are analyzed in the thesis,the core of Capon algorithm is to realize the minimum output without distortion by adjusting the beamforming weight vector in desired direction.However,because of the limitation of only using the horizontal degree of freedom,traditional Capon algorithm can`t shape efficiently and accurately according to user's angle information.Therefore,aiming at the limitation of above problem,3D Capon algorithm is proposed by increasing the vertical degree of freedom,then the improved algorithm is used for3 D MIMO scene.Meanwhile,for the problem that the complexity of improved algorithm is3O(n)in calculating beamforming weight vector,a 3D Capon optimization beamforming algorithm is proposed based on QR decomposition,the algorithm combines with the QR decomposition and the triangular matrix inversion algorithm,which reduce the complexity to2O(n).Furthermore,a multi-user beamforming scheme is designed by using the optimization algorithm.High rise scene and square scene as the actual multi-user beamforming scheme designed object and represent the vertical scene and horizontal scene respectively.According to the different distribution information of the user,the high-rise buildings is divided into three cases of situations,which are the same floor with different azimuth,the same azimuth in different floors and different azimuth in different floors.Also the square scene is divided into three cases of the same field area with different azimuth,the same azimuth in different field area and the different azimuth in different field area.Besides,all the above scenarios are verified by simulation.At this stage,the beamforming technology of 3D MIMO is studied,which can provide the key method for future 5G communication technology and it has certain practical significance.