 the UEs and the Node B, and the core network is modeled between the corresponding nodes and the RNC. As addressed in section 5.1, the modeling of the air interface and the core network are simplified in the developed simulation models. For modeling the air interface, statistic assumptions or traces from the radio simulations can be taken to model the most relevant air interface characteristics and the physical layer effects, e.g. propagation delay, Bit Error Rate (BER) over the air interface. Inter-cell interferences and power control are not important for the lub dimensioning as long as typical error rate and delay values at the air interface are modeled for individual users as well as per cell. The processing delays at the Node B and the UE in the UTRAN are also modeled as additional constant delay components of the end-to-end round trip time. With regard to the UMTS core network, its main impact on the lub dimensioning is the extra processing delays that need to be added to the end-to-end delay of a user flow, e.g. TCP RTT. Thus, a constant core network delay value is modeled in the simulation model. Similar consideration is done for modeling the external network, e.g. for modeling the Internet an Internet round trip time is added additionally to the end-to-end round trip time. This framework is also applied to the case when several Node Bs are connected to the RNC in the UTRAN. In this case, for each Node B the related UE entities, the air interface and the lub interface need to be modeled, and the RNC needs to identify the traffic from different Node Bs and control the resources of each Node B separately. The modeling of different UMTS networks share the same framework, but the detailed implementations of the UTRAN network or the air interface can be modified. In this thesis, the UMTS Rel99 simulation model is taken as the basic simulation model which is built according to this simulation model framework. Then for each evolved UMTS network, its 5 Introduction of Simulation Models specific new functions and 