An efficient and accurate OpenMP-MPI based 3D beam tracing method for radio propagation simulation in large scale urban environments

A modified adaptive division beam tracing (MADBT) technique based on the localized kd-tree and the OpenMP–MPI parallel techniques is presented for the simulation of radio propagation in large-scale urban environments. Beams launched from a transmitter are recursively traced by applying the MADBT method and beam trees recorded the propagation path info are generated. By traversing the beam trees, all the valid propagation (transmitted, reflected and diffracted) paths are efficiently determined. Then the receiver power strength can be calculated based on geometrical optics (GO) and uniform theory of diffraction along the arrival paths. By tracing the continuous beams instead of a number of rays, the proposed method performs higher efficiency than the widely used ray tracing method. During the beam tracing procedure, several techniques are adopted to accelerate the calculation. Firstly, a localized kd-tree is built according to the coverage area of the transmitter, which is more efficient than the global kd-tree to do the beam-triangle intersection during the tracing procedure. Secondly, a virtual simulation face is generated to speed up the searching for ray paths. Lastly, the OpenMP and the MPI parallel technique are implemented to further enhance efficiency of the proposed method. As expected, the simulated results for the realistic Malaysia urban environment show good agreement with measured results and performance high efficiency.