TABLE OF CONTENTS The development and application of new signal processing algorithms and, more generally, the optimisation of mobile communication systems are strongly related to the statistical properties of the propagation channel. New coding techniques, such as space-time coding algorithms, have been developed as a result of the fast growth in indoor communications coupled with a never-ending need for higher and higher data transmission rates. At the time that the previous COST 273 Action ended, the existing knowledge of channel characteristics was essentially based on data pertaining to path loss, delay spread and coherence bandwidth. However, because this knowledge proved to be incomplete for new systems, intensive research has been conducted concerning the deterministic propagation modelling and the estimation of channel parameters based on actual measurements.
The approach used for electromagnetic propagation modelling depends on the zone under study. For instance, if only the immediate vicinity of the antenna is to be considered, an integral method can be employed, while the coverage area of a transmitting antenna is usually determined via a ray method. Section 4.2 describes several recently proposed improvements to various existing techniques: integral methods, differential equation methods, parabolic equations, diffraction theory and Gaussian beams. If, as in the example mentioned above, the ray theory is applied to determine the coverage area of a BS, a large database is needed in order to accurately model the environment's electromagnetic and geometric...
