quirements determine the objective of dimensioning and the selection of suitable analytical dimensioning models. In this thesis two kinds of QoS are considered: user-relevant QoS and network- relevant QoS. User-relevant QoS refers to the QoS related to the individual user flow; while network-relevant QoS measures are used to evaluate the quality of the transport network such as packet delay and packet loss ratio. Since the characteristics and QoS requirements of different traffic types are essentially different, it is necessary to come up with distinct approaches for bandwidth dimensioning. X. Li, Radio Access Network Dimensioning for 3G UMTS, DOI 10.1007/978-3-8348-8111-39, Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH 2011 9 Conclusion and Outlook Dimensioning for Elastic Traffic for the user-relevant QoS Elastic traffic is associated with data applications, which use TCP for data transfer. The characteristic property of an elastic traffic flow is its rate adaptability, which is caused by the feedback mechanism of TCP. The transmission rate of a sender is adjusted to the available bandwidth along the route towards the receiver. As a consequence, the overall throughput, which is the user relevant QoS measure for elastic traffic, depends not only on the link capacities, but also on the number of concurrent flows. The proposed dimensioning model for guaranteeing the application throughput for the elastic traffic is the processor sharing model. The theory of processor sharing is applied to the dimensioning of networks for elastic traffic. In the context of this thesis, processor sharing is interpreted as ideal bandwidth sharing among flows, whose arrival instances form a Poisson process and whose service times are generally distributed. The basic processor sharing model, i.e. the M/G/R-PS model, which has been proposed in the literature, is investigated and deficiencies are identified. The main contributions of this thesis is to apply the processor sharing model for dimensioning the UMTS networks to me