 a range of hb from 0 to 50 m. Physical Deployment When assuming a cell radius of 2000 m, services up to 144 kbit/s apply; and with a cell radius of 500, services above 144 kbps (e.g. 384 kbps) apply. If the BS antenna height remains above the average roof top height of 15 m, a hexagonal cell lay out with dis- tances between base stations equal to 6 km can serve as reference. Figure 2.7 illustrates this type of tri-sectored cells using the GSM based antenna pattern shown in Figure 2.8. Mobility Model The vehicular reference mobility model uses a pseudorandom mobility model with semi-directed trajectories, the mobile's position gets updated according to the de- correlation length and direction can change at each position update following a given probability within a sector. For a reference example, we can assume constant mobile speeds of 120 km/h, with a direction probability change at position update of 0.2, and a maximal angle for direction update of 45°. Mobiles get uniformly distributed on the map and their direction randomly chosen at initialization [2]. System Analysis Fundamentals Figure 2.7 Vehicular deployment model. -180-150-120 -90 -60 -30 0 30 60 90 120 150 180 Angle (degrees) Main sector 90 deg Figure 2.8 Horizontal antenna pattern example based on GSM three sectored antenna [2]. 2.2.6 Mixed Here we illustrate a mix environment by a vehicular (macrocells) and an outdoor to indoor (microcells) environment taking place in the same geographical area. In this area, fast moving terminals (e.g. vehicles, trains) will most likely connect to the macro- cells to reduce the hand-off rate (number of hand-offs per minute) and slow moving terminals (pedestrians, boats on a shore) will probably connect to the microcells to achieve high capacity. The reference assumptions [2] about combined outdoor and ve- hicular physical deployment environments can be as follows: the log-normal standard deviations = 10 dB for both outdoor and vehicular environments, mobile speeds are 3 The UMTS Network and Radio Access Technology 