Virtual Array Based Millimeter Wave MIMO Channel Measurement And Analysis Of Beamforming Algorithm

The demand of new generation mobile communication systems for large capacity and high rate data transmission ability promotes the development of millimeter wave communication technology.The future millimeter-wave communication systems mainly apply to the indoor complex scenario.Current researches on this scenario have some problems,such as lack of measurement data and narrowly focused measurement scenario,which is difficult to satisfy the actual needs.Similarly,the researches of beam-forming algorithms also have the problem of narrowly focused simulation scenario and being divorced from the real scenario.Therefore,it is necessary to measure indoor complex scenarios in millimeter wave frequency band.This thesis aims to explore the propagation characteristics of millimeter wave 3D MIMO channel,design a measurement system based on the Vector Network Analyzer,extract the channel parameters from measurement date,study the propagation characteristics of millimeter wave,and analyse the performance of beam-forming algorithms from the perspective of channel measurement.The main research work is summarized as follows:(1)Millimeter wave 3D MIMO channel measurement and channel characteristics analysis.The indoor MIMO channel propagation measurement platform is built based on the Vector Network Analyzer.Based on IFFT omnidirectional scanning channel estimation algorithm,channel parameters such as time delay,angle and power can be extracted from the frequency domain sampling data,and the propagation characteristics of MIMO channel are obtained.Two measurement scenarios,empty hall and staircase conference room are selected as samples.The former environment can verify the reliability of the measurement system and data processing,while the latter can compare the channel characteristics of the two scenes.The results show that the millimeter wave channel has sparse characteristics.To some extent,the material with lower penetration loss has little influence on the propagation of millimeter wave,hence the path prediction related to the material can be simplified.The number of multipaths and the angles between multipaths affect the root mean square delay spread and the root mean square angle spread.At the same time,the influence of antenna array on channel characteristics is discussed.(2)Performance analysis of beam-forming algorithms based on millimeter-wave3 D MIMO channel data.Based on the millimeter-wave propagation coefficients of the above two measurement scenarios,the performance of the beam-forming algorithm is compared and analysed from three aspects of directivity,anti-interference and system transmission rate.The results show that the simulation and measurement of the low complexity hybrid beam-forming algorithm have good directivity,and the directivity performance is close to the classical Zero Forcing algorithm and Minimum Mean Square Error algorithm.If the interference between users is within the tolerance range of the system,the hybrid beam-forming algorithm can effectively reduce the signal processing burden and the hardware cost.