Research On Transmission Scheme Of 3D Massive MIMO Communication System

In recent years, Massive MIMO has become the focus of the development of mobile communications. it is a key future technology for mobile communications. Considering 5G mobile communication system development, Massive MIMO channel modeling also needs to be expanded from 2D space to 3D space. When the Base Station in Massive MIMO system is deployed with large scale uniform linear arrays with half-wavelength spacing, it will occupy large space. Under this condition, dual polarized antennas may alleviate this problem. Therefore, this paper will propose a transmission scheme based on large-scale 3D dual-polarized MIMO system. In addition, for large-scale MIMO system the beamspace channel energy is not completely focused, the paper will also study the problem to improve the concentration of massive MIMO system.Firstly, this paper analyzes the basis for large-scale MIMO transmission technology. The paper give the analysis of the massive MIMO channel capacity, including from point to point MIMO system to a large scale MIMO system capacity analysis, and from multi-user MIMO system to massive MIMO channel capacity analysis, then the paper will introduce the channel modeling methods based on 3D MIMO channel, including non-physical channel model and physical channel model, and the dual-polarized MIMO channel model, and finally, the paper will on gives a simple introduction of the beamforming technology for MIMO system.Then, this paper will study the transmission scheme for massive MIMO when the BS is deployed with dual-polarized antennas. The paper will first design the beamspace channel to ensure the base station side beamspace channel orthogonal to each other, then based on maximum system rate as a criterion for user scheduling, and BS schedule the users in the cell with the greedy algorithm. Each user is scheduled to communicate with non-overlapping beams with the base station, to ensure noninterference between users. Simulation results show that dual-polarized antenna system can guarantee system throughoutput and occupy less space.Finally, the paper will propose two massive MIMO beamspace beam leakage suppression schemes. Two programs are proposed in the implementation of the base station side, the first is a diagonal matrix shaping, the second scheme design the matched-filter matrix based on the real-time channel. Both schemes are based on the maximum beamspace channel energy to interference ratio guideline. The two scheduled can improve the concentration of the beamspace channel, thus will increase the whole system throughoutput. Simulation results show that the two methods can improve the distribution of channel energy and the matched-filter matrix scheme performs better.