(A) deterministic ray tube method for wave propagation predictions in urban microcellular and indoor environments

Abstract

In this dissertation, we have developed a new ray tracing method (Deterministic Ray Tube method) that can provide accurate site-specific propagation predictions in heterogeneous urban microcellular and indoor environments. The method is based on image theory and has high computational efficiency and accuracy, compared to the precedent methods resorting to the SBR (shoot and bounce ray) scheme.

In the Deterministic Ray Tube (DRT) method, three kinds of ray tubes are defined and treated in a simple and unified manner. (In the indoor environment, four kinds of ray tubes are considered.) The DRT approach can be used for any complex propagation environment with arbitrary building layouts and heights, and find all propagation paths from a transmitter to a receiver extensively without redundant computations. In addition, since it is fundamentally a point-to-point tracing technique based on the image concept, it does not require reception tests and guarantees high accuracy. Its computational efficiency is also as high as the image method.

First, we describe the theoretical basis of the DRT method for urban microcellular environments in detail. The quasi and full three-dimensional DRT methods are described and a new hybrid method combining the UTD with the near-field ray calculation method is proposed to determine the diffraction loss due to propagation over buildings with irregular heights and spacings. The validity of the DRT method is discussed by means of comparisons with measurements. Two measurement campaigns conducted in Ottawa, Canada and Munich, Germany are described and compared results are reported in detail.

Second, the DRT method is applied to the indoor environment in consideration of transmitted rays through walls and the prediction results are compared with the published measurements.

Finally, the possible prediction errors of the ray tracing model are discussed. The effects of building position tolerances as well as e...