Research On Performance Analysis And Feedback Technology For Wireless Communication Systems With Large-Scale Antenna Array

With the growing demand for wireless communication capability, wireless communications development will become faster and smarter. In order to meet the requirement on large capacity, highdata rate and high reliability of the wireless communications, large-scale antenna array system is widely employed, which requires the research on3D channel modeling, new transmission schemes, and efficient feedback technology in both academics and industry, on which this paper focuses.This paper introduces the classic2D channel model, and then the modeling of3D channel which differs from2D one in the introduction of the elevation angles. The improved3D channel model is the basis of the subsequent works.Next, based on the MU-MIMO downlink single-cell system model, the "channel hardening" feature of the large-scale antenna array systems is presented. The correlation feature of the Rayleigh channel and3D MIMO channel is analyzed in terms of correlation coefficient, condition number and eigenvalue, and the analysis shows the inter-user channel correlation reduces in the case of large-scale antenna array systems. Moreover, given the full CSI, the bound of spectrum efficiency is derived for both Maximum Ratio Transmission (MRT) and Zero Forcing (ZF) linear precoder. Also the effect on spectral efficiency and BLER performance by several factors via simulations, and the results show that the simple linear pre-coding such as ZF can eliminate intra-cell interference, and increasement of antennas can improve the spectral efficiency and transmission reliability.Finally, based on the analysis of the effect of concentrated SINR distribution from the viewpoint of "channel hardening" and the simulation results of CQI distribution for antenna array with128elements and8ones, two feedback schemes are proposed:increasing the feedback cycle, and CQI differentials feedback. The simulation results verify these two schemes can reduce feedback overhead without any throughput loss. Morevoer, the necessity of introducing256QAM is addressed for large-scale antenna array systems, and corresponding MCS recommendation and SNR-BLER interface curve under AWGN channel are given.