Physical and statistical modelling of radiowave propagation.
The widespread use of radio frequencies of wavelengths small compared with the
major terrain irregularities has led to the development of theoretical deterministic
models for the prediction of field strengths over paths of given profile. The
examination of these models is the main objective of the present thesis. Although
present radio links are mainly based on empirical developments, theoretical approaches
may offer considerable alternative for the design of future wireless communications
It is well known that the methods applied are based on multidimensional integral
equations, which only in certain and idealised cases reduce to a practical form suitable
for realistic utilisation. The present work attempts to reveal the physical processes that
characterise the radio channel and how these are approached by certain models for
common engineering applications. Since the major mechanism of propagation in radio
environments is diffraction, extensive analysis is performed for this physical process.
In particular, a new fast implementation of the Vogler multiple knife-edge diffraction
algorithm is described with the additional benefit of improved accuracy at path profile
configurations where the original solution fails considerably. An entirely new approach
to slope-Uniform Theory of Diffraction is introduced and shown to produce essentially
identical results to Vogler within much shorter computation times. This is applied to
3D urban propagation and to terrestrial fixed links and is shown to produce accurate
results compared with measurements.
Finally, new physical-statistical models are introduced in order to overcome the
excessive cost of high resolution building databases. Application to both mobilesatellite
and to broadband fixed access systems revealed a high degree of statistical