Intelligent Ray Tracing (IRT)

Accelerate ray-optical models by combining the advantages of ray-optical and empirical models.

Motivation for the Intelligent Ray Tracing (IRT)

Ray-optical models are time-consuming because all possible rays must be tracked. A new approach to the acceleration of ray-optical models reduces the computation time to that of empirical models. This method combines the advantages of both ray-optical models and neglects their disadvantages. It is based on a single preprocessing of the building database. All walls of the buildings are subdivided into tiles, and all wedges are subdivided into segments. The visibility relations between all tiles, segments and receiving points in the database are computed in the preprocessing stage because they are independent of the transmitter location.

Propagation Paths

This deterministic model allows a very accurate rigorous 3D ray-tracing prediction because many interactions can be taken into account. The selection of propagation paths is similar to the method for standard ray-tracing (SRT). As a result, rays can either be selected by using a selection file (.sel file) and choosing the option, Only user defined propagation paths or the option Number of interactions. Therefore each transmission through a wall, each reflection at a wall and each diffraction at an edge counts as an interaction. Due to a preprocessing of the database, the IRT model has a very short computation time.

Computation of Each Ray’s Contribution

For the computation of the rays, not only the free space loss has to be considered but also the loss due to the transmission, reflection and (multiple) diffraction(s). This is either done using a physical deterministic model or using an empirical model similar to the method for the standard ray-tracing (SRT) mentioned.

Note: This does only affect the determination of the transmission, reflection, and diffraction coefficients. The prediction itself always remains a deterministic one. Thus the same rays are taken into account.