Mean value Mean value of all routes 108.1 (distance = 25-50 m) The received power values lead to a pattern which is technique (i.e. the determination of the pixel matrices compared to the database entries to determine the loca- and the computation of the entries of the look-up table) is tion of the MT. Figure 4.7-23 shows the achieved results higher than the effort for conventional approaches. But for the test scenario. The initial effort for the location the achievable localisation accuracy is significantly better (a) COST 231-Hata model. (b) 2.5 RT model. Figure 4.7-22 Field prediction over a section of central Paris. Propagation modelling and channel characterisation CHAPTER 4.7 could guarantee a good accuracy with a drastic reduction in computation time with respect to conventional ray models, although the output is often limited to field strength and fading statistics. Therefore, these models are suitable for simple field predictions involving a large number of trial runs, such as those required for mobile radio network planning and deployment assessments. A simplified model for field prediction in the urban environment is described in [BCFF02]. The model is de- rived from the observation that propagation in the urban environment may occur owing to different mechanisms, Figure 4.7-23 Real (black) and estimated (grey) route of a walk namely LoS propagation when there is a direct path be- through the city-centre of Stuttgart, depicted area: 2.5 km X 2 km. tween the two terminals, lateral NLoS propagation along the streets and around the building corners, and vertical if really accurate prediction models like 3D RT or other NLoS over the building rooftops. For LoS propagation the accurate models (like the dominant path approach, see authors resort to the well-known two-ray propagation Subsection 4.7.3.7) are used. model (including the direct ray and the ground reflected Ray models can be of great help in the optimisation ray), while for the two NLoS components they developed phase of an existing mobile radio sy