Researches On Ray Tracing Technology In Massive MIMO Deterministic Modeling

Massive MIMO (Massive Multiple-Input Multiple-Output) has emerged as one technology enabler for the next generation mobile communications called5G (Fifth-generation). The gains promised by Massive MIMO are augured to overcome the capacity crunch in today’s mobile networks and to pave the way for the ambitious targets of5G. Massive MIMO systems are equipped with a large number (dozens or hundreds) of antenna elements at the base station which is used to serve tens of UEs simultaneously. Theory and measurement results indicate that Massive MIMO can offer significant increases in data throughput and link reliability without extra bandwidth or boosting transmission power. As the first step to evaluate the performance of any communication systems, the accurate and efficient channel models for massive MIMO are indispensable to be investigated for the sake of Massive MIMO system design and performance evaluation.Therefore, the precise channel models and the configuration of the antenna array are critical factors for working out the main properties of Massive MIMO channels. Due to the considerable attenuation of Massive MIMO technology, this dissertation researches the ray tracing based on electromagnetic theory and the theory of geometrical optics in deterministic channel modeling. The main works are as follows:(1)Based on the specific geometry information, location information and relative dielectric constant and magnetic permeability of structural surface materials in the modeling scene, structures are simplified as objects which are made up of multiple rectangular plane. Each plane’s vertex information is stored counter-clockwise. According to the actual scene information to set the height and position of the Mechanical Engineering Building and Civil Engineering Building of Beijing Jiaotong University, a Massive MIMO wireless channel simulation platform has been generated.(2)By placing different antenna array positions, constructed two scenarios which include LOS (Line of Sight) and NLOS (Non-line of Sight). The linear antenna array and circular antenna array are designed at the maximum number of128. On this basis, different antenna arrays and different scenarios along Massive MIMO can be compared to explore wireless channel characteristics and to be used for theoretical analysis.(3)A11of propagation paths including direct paths, reflection and scattering are described by rays through electromagnetic calculation along the modeled scene and different antenna arrays. Then comprehensively analyze Massive MIMO channel characteristics and propagation properties using various channel parameters involving electric field intensity described in the plural form, the time delay, the angle of arrival and the angle of departure. Put forward a channel parameter analysis method based on Massive MIMO which can be used to explore Massive MIMO channel characteristics and propagation properties. What’s more, this channel parameter analysis method can provide effective theoretical support for5G large-scale antenna array channel practical application.