  Ray tracing is an efficient channel modeling method. However, the traditional
ray tracing method has high computation complexity. To solve this problem, an
improved bounding volume hierarchies (BVH) algorithm is proposed in this paper.
Based on surface area heuristic (SAH) and spatial distance, the proposed
algorithm can effectively reduce the number of unnecessary intersection tests
between ray and triangular facets. In addition, the algorithm fully considers
the influence of ray action range, which can not only make up for the defects
of spatial division based on uniform grid method and k-dimensional (KD) tree,
but also solve the problem of unsatisfactory spatial division based on
traditional BVH algorithm. The simulation results show that compared with the
traditional BVH algorithm, the proposed algorithm can improve the computation
efficiency by 20% to 35% while ensuring the computation accuracy.
