Research On Wireless Channel Characteristics Of Massive MIMO Based On Measurement

With the continuing explosive growth of the number of smart mobile devices,people's demand for higher-performance mobile communications is increasing.As a key technology to improve the capacity and spectrum utilization of communication systems,MIMO(Multiple Input Multiple Output)has been a research hotspot in the field of wireless communications.Today,the 5G(Fifth Generation)era has arrived ahead of time with the joint efforts of the world.MIMO technology has developed into Massive MIMO technology which is more powerful,and Massive MIMO technology has become one of the key technologies of 5G mobile communications.The performance of communication systems is often limited by the channel characteristics in real propagation scenes.Compared with the outdoor environment,the indoor environment is more complex and changeable.Nowadays,many wireless communication services occur in indoor places such as office buildings.Considering the characteristics of 5G's micro base stations,there will be more micro base stations deployed in indoor environments.The focus of external research is more on high frequency bands above 6GHz in outdoor environments,while the research on frequency bands below 6GHz in indoor environments is relatively rare.At the same time,the measurement platforms used by most research institutions are expensive,and it is necessary to design and build relatively inexpensive measurement platforms that support Massive MIMO channel.This paper designs and builds a Massive MIMO channel measurement platform,and conducts actual measurement and research on the important topic of wireless channel characteristics that Massive MIMO system exhibits in typical indoor environments.The specific work includes the following aspects:(1)The propagation characteristics of wireless channel are described,including large-scale fading and small-scale fading,and the modeling principles and measurement methods of wireless channel are introduced to lay the foundation for the full paper.(2)Designs and builds a broadband Massive MIMO wireless channel measurement platform independently,and develops a software control program for the measurement platform independently by using LabVIEW software.The measurement platform can provide up to 256 channels,and supports actual measurement of Massive MIMO channel.The measurement platform can realize large-scale and automatic measurement of multi-antenna wireless channel frequency responses in a typical indoor environment.(3)Designs a complete measurement program,and uses the measurement platform to conduct large-scale measurement of Massive MIMO channel in multiple typical indoor scenes to obtain sufficient measured data of frequency response.The measurement includes LOS(Line of Sight)and NLOS(Not Line of Sight)scenes in multiple environments such as corridor,conference room and office,covering three sets of frequency bands.(4)By processing the measured data,the characteristic parameters of the indoor Massive MIMO wireless channel are extracted,and the single-user Massive MIMO wireless channel characteristics of multiple typical indoor scenes and multiple groups of frequency bands are studied and analyzed,thereby provides reference value for system design,network optimization and performance evaluation of indoor wireless communication system.(5)Compares the differentiating capabilities of users under different antenna numbers,different scenarios,and different frequency bands through 3D MIMO(Three Dimensions MIMO)system in a typical indoor environment,and provides a reference for the application of 3D MIMO communication systems in indoor environments.