Research Of The Massive MIMO Propagation Characteristics Based On Theoretical Methods

The rapid development of wireless communication affects all aspects of people's work and life?5G is a new generation of mobile communication system developed to meet the demand of mobile communication after 2020?It will have higher energy efficiency and spectrum utilization than existing 4G communication systems,and the wireless coverage performance,transmission latency,system security and user experience will also increase dramatically.5G will be closely integrated with other new wireless mobile technologies to lead us into a new era of all-things interconnection,which also means unprecedented opportunities and challenges.The massive multiple input and multiple output(Massive MIMO)system,equipped large-scale antenna array in the base station,can greatly improve the data transmission speed and the system capacity and achieve the maximum utilization of the time and space resources.It is considered as the most potential and energy-efficient technology in the future 5G.The quality and performance of wireless communication systems have a strong dependence on the wireless channel.The propagation characteristics of wireless channel is an important basis for the design and deployment of wireless communication system.Obtaining channel state information from channel characteristics studying is crucial for the design and performance evaluation of the Massive MIMO system.Channel modeling for the Massive MIMO systems is of key importance to Massive MIMO's successful application to 5G.In this paper,Massive MIMO system is constructed by using the method of propagation graph theory modeling.Combined with the actual channel measurement,the rationality and accuracy of the propagation graph theory method are analyzed by comparing the theoretical simulation results with the measured data,and the parameters are extracted and analyzed.We firstly introduce the fading characteristic and modeling method of wireless channel.Secondly,we introduce the principle,modeling process of the propagation graph theory and the improved algorithm based on scatter propagation mechanism.According to the selected indoor scene,the barrier wall area is divided into discrete scatterers with different unit areas.Then determine the visibility of the transceiver antenna and scatterers and build a complete propagation diagram.The channel frequency transfer function and time-domain impulse response can be obtained by matrix operation.In addition,massive MIMO system channel measurement was carried out on the selected scene,equipped with 64 real line arrays with the frequency of 4.45GHz.The modeling results and the measured results are compared and analyzed.Furthermore,using the propagation graph theory method,the 128-element massive MIMO system is modeled with frequencies of 1.4725GHz and 6GHz respectively.The parameters of the simulated channel response are extracted.The angle domain,delay domain characteristics and channel orthogonality of the massive MIMO system are analyzed.