Rearch On Ray-tracing Propagation Model For Next Generation Wireless Communication System

The next generation wireless communication system(NGWCS)supporting high-speed,low latency,ultra-high traffic density and full coverage services is urgently required for high-speed user experience,massive Internet of things terminal access,ultra high-speed mobile scenarios,etc.The wireless channel characteristics are fundamental and crucial for designing NGWCS,and therefore the accurate prediction of channel characteristics is the existing pivotal problem.The development and application of high-performance ray-tracing propagation model(RTPM)is a powerful solution.This paper is focused on the research of RTPM for NGWCS,the main work and contributions of this paper are as follows,(1)A three-dimensional and efficient RTPM for massive MIMO channel prediction based on the ray-launching method and the space-subdivision acceleration algorithm is advanced.The number of ray-object intersection tests can be significantly reduced according to the adjacent relationships between tetrahedrons,and therefore the computational efficiency of massive MIMO channel link simulation can be improved.Channel measurements have been performed using a64-elements planar massive MIMO system,and the accuracy of the model is verified.(2)A polarized RTPM considering random antenna inclination angle(AIA)is advanced for the D2 D scenario with randomly moving and swingwing terminals.The radiation patterns of antenna with arbitrary AIA is derived based on the coordinate transformation and incorporated into the spatial-subdivision RTPM.Moreover,a flexible and adjustable AIA model is advanced to characterize the random swing of terminals.The accuracy of the model is verified with the comparation between the simulation and measurement results.The influence of channel depolarization and random AIA on the received signal is analyzed and a statistical channel model considering the AIA effect is established according to the statistical analyses.(3)A simple and efficient real-time RTPM is advanced for the scenarios with moving scatterers(MS).The scenario preprocessing can be simplified with a predefined active area since scenario remodeling resulted from MS is unnecessary.A method based on surface attribute transformation is advanced and can be combined with various velocity models to imitate the random movements of scatterers.Moreover,an adaptive ray-launching technique is advanced to improve the simulation efficiency of the model.The model is applied to an indoor scenario with pedestrians,and the effectiveness and accuracy of the model are verified by comparing with the measurement results.(4)A flexible and universal real-time RTPM is advanced for the scenarios with MS.The static scenario and MS are modeled independly leading to the movement of scatterer is continuous in time and space and readily available for various MS models.Furthermore,a modified space-subdivision RT algorithm considering MS effect is advanced.The model is applied to an indoor intensive user scenario and an outdoor vehicle-to-vehicle scenario,respectively and the excellent performance is indicated.