Research And Analysis Of Massive MIMO Channel Modeling And Spatial Correlation

The development of information globalization has made wireless communication gradually penetrate into all aspects of people's lives,and it is also related to the development of my country's economy and culture,and is the basic guarantee for my country's development and modernization.Wireless transmission technology is the most innovative and effective means.At present,the research on wireless communication system has developed to the Fifth Generation(5G)/Beyond Fifth Generation(B5G).Massive multi-input multi-output(MIMO)technology,as one of the key technologies of 5G and even B5 G,has become one of the hot research hot spots.The Massive MIMO system is equipped with hundreds of antenna units at both the receiver and transmitter,and the beamforming technology is used to achieve the purpose of simultaneous transmission of multiple signals under the same time-frequency resources and different spaces,so as to achieve efficient use of spectrum resources.In order to fully utilize the potential of Massive MIMO in improving system capacity and spectrum utilization,mastering channel characteristics are a prerequisite.Based around a Massive MIMO channel modeling was discussed,based on the channel characteristics of the wireless channels,especially the correlation with the airspace of the channel estimation is crucial for in-depth research.Firstly,combined with uniform linear antenna array and uniform circular array,the approximate expression of the spatial correlation function(SFC)of the angle of arrival(AOA)of the incident signals to the application environment of macro and micro cells was derived,and the small angle approximation had been extended for the case of the large angle distribution,and three typical incident signals were obtained.The approximate solution of SFC under angular distribution(uniform distribution,Gaussian distribution and Laplace distribution),the influence of angle spread for SFC was analyzed.And the simulation verified the improvement in the computational efficiency of the approximate expression and the high degree of fit between the theoretical expression and the approximate expression.Secondly,according to the characteristics of SFC,the MIMO channel model was reconstructed for the special random environment such as the Internet of Things application.For the theoretical models of the distribution of the AOA of various incident signals and the measured data obtained through the estimation of the direction of arrival of the channel,a simplified model based on the power spectrum of any incident angle of arrival was proposed.The influence of different sampling pulses and different weight coefficients on the calculation accuracy of the simplified model was discussed and compared.The calculation efficiency and fitting accuracy of the simplified model were considered through simulation verification.It is verified that the simplified model is suitable for AOA power spectrum in any environment by von Mises(VM)distribution,exponential distribution in asymmetric geometric model,and truncated Laplace distribution in dense urban channel model.Finally,considering the large antenna arrays,especially the mutual coupling between antenna arrays in the millimeter wave communication effect,based on arbitrary AOA spectrum sampling basis function under the mutual coupling effect of the correlation of simplified model,the mutual coupling effect was deduced under arbitrary AOA power spectrum of the closed expression,analyzed the mutual coupling effect on the system,the influence of the based on the exponential distribution and so on.The variation trend of SFC and system capacity with and without mutual coupling was discussed in detail.Simulation analysis verifies that the expression proposed in this paper has a good fitting effect with the theoretical results.In addition,the calculation time can be greatly reduced,the calculation efficiency can be improved,and the design requirements of the actual channel can be met.