Improvement of ray tracing in urban street cell environment of non line-of-site (NLOS) with consideration of building corner and its surface roughness

摘要

Mobile networks employing higher data rate and speed have been investigated for deployment of 5G mobile communication systems in urban microcellular environment. One of the approaches to achieve this goal, frequencies between 6 and 100 GHz are candidate to be utilized due to rich frequency spectrum. However radio propagation loss in these high frequencies is not characterized yet. Ray tracing (RT) method is one of the common technique, though the accuracy degrades as frequency becomes higher. In this paper, alternative model considering detailed building corner in intersection is proposed whereas building corner is, conventionally, assumed to be right-angle wedge shape. The proposed model also takes into account for surface roughness in order to enhance the accuracy for high frequencies. The parameter of surface roughness is optimized by comparing with measurement result. The proposed model with optimal size of surface roughness helps enhance accuracy, especially for high frequencies, compared with conventional wedge corner model. Accumulative error in terms of frequency can be resolved by the proposed model. Further discussion is described to develop the proposed model for better prediction applicable in both low and high frequency bands.