in the cell, resulting in over-dimensioning for PS services. Thus, other types of distribution should also be considered. 6 For example e-commerce, on line banking, file transfer, information DB access, etc. The UMTS Network and Radio Access Technology ESTABLISHING SERVICE MODELS Before deploying new elements in a mobile telecommunications network, whether it is an existing system based on 2nd generation (2G) technology like GSM, or a new one like UMTS, we will need a projection for the potential number of subscribers. In this chapter, we consider a field study to extrapolate some subscriber numbers from two growth forecast assumptions. Although these projections will not necessarily apply to a particular deployment scenario, it will serve to illustrate network dimensioning based on the split of voice only and combined (voice + data) services. In Table 7.1 we illustrate estimations for a 10-year period where 2G values correspond primarily to GSM voice services and 3G values to data starting with GPRS in the 1st 2 years. Thereafter, full multimedia services expand rapidly at the introduction of UMTS in existing GSM networks. A major breaking point occurs around 2005 with high predominance of 3G type services. Table 7.1 Subscriber Growth Within a 10-year Period (in 1000s) Subscribers Year: Total In Table 7.2 we illustrate the subscriber growth beginning in 2002 when penetration of data has already reached about 30% of the total traffic. Here we assume that GPRS car- rying wireless IP type services has grown to non-negligible levels right before the intro- duction of UMTS. Despite the stretch to a 15-year period, 2005 stands again as the breaking point towards full predominance of multimedia services. Nonetheless, as in the projections of the 10-year period, voice only services will remain a good 25% of all traffic. Table 7.2 Subscriber Growth Within a 15-year Period (in 1000s) Subscribers Year: Voice Voice + data Total After 2005 in both cases the subscriber growth appears low. This can reflect the fact that the ov