oad distributions), the performance of the networks and end users, the bandwidth utilizations, the achieved multiplexing gains, and in turn have significant influence on the dimensioning results. The dimensioning process is the core of this dimensioning framework. It relies on the two inputs (i.e. traffic demand and desired QoS targets), and the given network configurations. 4 Framework of UMTS Network Dimensioning The output of the dimensioning process is the minimum required link capacity which should support the offered traffic demand while satisfying the desired QoS requirements. The detailed procedure for the network dimensioning is shown in Figure 4.5. It basically contains three steps. Step 1: Check the input data and parameters. It includes three subtasks: analyze the traffic, check the network configurations, and identify the QoS targets as the objectives for the dimensioning. Step 2: Select an appropriate dimensioning method. It can be either a simulation approach or an analytical approach. If using a simulation approach, a simulation model with UMTS functionalities needs to be set up and verified. The advantage of the simulation approach is that it can model detailed protocol behaviors, functions, traffic patterns, network topologies etc., which will give a rather accurate outcome. However, its main drawback is the high effort on implementing the simulation model and performing simulations. The analytical approach is usually preferred whenever it is available due to its low effort and easy implementation while it can achieve an acceptable accuracy on the results, though not all details can be modeled and more assumptions need to be taken. The selection of which analytical model to use for the dimensioning depends on the given traffic (i.e. traffic class, traffic mix), the network configurations and required QoS targets. Step 3: This step is to process the dimensioning with the selected dimensioning method. The outcomes of the analysis on the traffic, network configurations and QoS requirements in step 