Effects Of Microcellular Environment Information To The Prediction Accuracy Of Ray Tracing Algorithm

With the rapid development of mobile communication, people’s requirement for the quality and quantity of communication is becoming higher and higher, which puts forward higher requirements for the rational implementation of network planning. Before determining the planning and implementing the design of wireless communication system, the radio wave propagation characteristics under corresponding environment must be known. Outdoor microcellular environment is a typical mobile communication scenario, so it will be significant to study the propagation characteristic of radio wave under corresponding circumstance. Ray tracing(RT) algorithm, because of its simple operation and high accuracy, has become a typical deterministic approach of studying wave propagation characteristics. And this method was used in this paper to analyze wave propagation related problems in outdoor microcell scenario.In this paper, all researches on the propagation characteristics of radio wave under microcellular scenarios are based on the prediction of ray tracing algorithm which based on virtual source tree. Therefore, the theoretical basis and basic operating procedures of ray-tracing algorithm based on the virtual source tree were introduced firstly, and related simulation parameters, such as path loss and RMS delay spread, are also been introduced briefly.After getting familiar with the operating procedures of ray tracing algorithm based prediction model, the study about the impact of error for environmental information on prediction results was studied. The environmental information of microcellular scenarios consists two parts of contents, namely geometry and electrical parameters. The environmental geometric information can be obtained by the city digital map. In order to study the error’s influence of environmental geometry information on the accuracy of prediction results of RT algorithm under outdoor microcellular environment, two different types of error maps were generated based on the original digital map, and then the simulation was based on these error maps which has different size of error. And finally, in order to learn the influence of geometric error on accuracy of predicted results of ray tracing model, the simulations results were compared with original map corresponding simulation results. On the other hand, on account of electrical parameters’ impaction on accuracy of predicted results of RT model, the dielectric constant and conductivity of building materials were set with different values. And then to further understand the impact of electrical parameters on prediction results of RT model, the path loss and RMS delay spread under same circumstances have been simulated by using RT prediction model.In addition, due to the fact that communication frequency has been tending to develop higher and higher, the high-frequency(20GHz) signal’s transmission characteristics at outdoor microcellular environment were also studied in this paper, while when the signal frequency is higher than 10 GHz, the rain caused attenuation becomes non-negligible, so the rainfall attenuation was also added into the RT model. It showed that the rainfall has a significant effect on prediction results of ray tracing algorithm based model.