th loss than that of urban and suburban areas. In mountainous areas we can apply a path loss rule closer to R-2 assuming that BS locations do not suf- fer from blocking. Vehicle speeds set Rayleigh fading rates. The vehicular environment applies to scenarios in urban and suburban areas outside the high rise core where the buildings have nearly uniform height. In this model, the BS has antenna height above rooftop level with QM as the factor depending on the relative height of the BS antenna (2.43) where hb is the height difference between BS antenna and the mean building rooftop height, and b is the average separation between rows of buildings. Then the total trans- mission loss for the above rooftop case becomes: 2 1.8 (2.44) The UMTS Network and Radio Access Technology In the building environment, measurements [16] showed that the path loss slope be- haves as a linear function of the base station antenna height relative to the average roof- top h. Then, the above path loss equation can be defined as: (2.45) where (2.46) hm is the difference between the mean building height and the mobile antenna height; and x is the horizontal distance between the mobile and the diffracting edges. If hm = 10.5 m, X = 15 m, and b = 80 m, typical urban and suburban environment val- ues with average four story building heights, then the above path loss expression L re- duces to a simple function of the transmitter to receiver distance R (km). We measure the BS antenna height from the average rooftop hb in metres, and frequency f in MHz. (2.47) When we assume a fixed BS antenna height of 15 m above the average rooftop, i.e. hb = 15 m, and a carrier frequency of 2000 MHz, the vehicular path loss L becomes: L = 128.1+37.6log.(R) (2.48) L shall in no circumstances be less than the free space loss. This model applies to the Non-Line of Sight (NLOS) case only and describes the worse case propagation. Log- normal shadow fading with 10 dB standard deviation are assumed in both urban and suburban areas [2]. The path loss model is valid for