bursty traffic. Due to the potential multiplexing gain, overbooking becomes possible to increase the utilization of the available resources. It has become an efficient way to improve bandwidth utilization and network efficiency, thereby increasing the revenue generated by a network infrastructure. However, for a cost-efficient network dimensioning, overbooking should be performed appropriately: too much overbooking causes degradation of QoS for the existing customers whereas too little overbooking leads to underutilization of available bandwidth. Thus, finding an optimum overbooking is an essential task for network dimensioning. 8.1 Overview and Objectives Overbooking has been studied for ATM and IP networks. Pazos and Gerla studied overbooking in the use of ATM ABR services on Internet backbones [CM98a]. [CM98b, TS96] demonstrated overbooking is a reliable alternative to increase link utilization in ATM networks. The IETF draft [CI01] addresses the notion of overbooking and its application to IP/MPLS traffic engineering. Besides, there are studies focused on finding approaches of determining the optimum overbooking factor for the Internet backbone networks [RM*04, HDB*04]. In the star topology multi-lub radio access network, overbooking is used to allocate less bandwidth on the backbone link than the total bandwidth request of all the connected last mile links. The lub backbone links can be overbooked by taking advantage of statistical multiplexing gain among traffic from different Node Bs. The achievable statistical multiplexing is dependent on the network scale (number of Node Bs/last mile links), trunk types, traffic types and user traffic characteristics. Thus, these aspects will be considered in setting an appropriate overbooking for a cost-efficient dimensioning. In this thesis, the overbooking factor (OB_factor) is used to specify the degree of overbooking. Assuming there are n Node Bs in the radio access network, each Node B has a last mile link rate Cac_i and the lub backbone link has a capacity of Cbb,