The tendency in future mobile Radio Access Networks (RANs) consists in an increase of new and Internet Protocol (IP)-based services with strict requirements regarding bandwidth and Quality of Service (QoS) and in a dominance of packet data traffic in future mobile networks. Existing mobile networks (e.g. Universal Mobile Telecommunications System (UMTS) Release 99 (R99)), which are designed assuming a predominance of circuit switched traffic, are not suitable to efficiently carry IP traffic under consideration of the hierarchical and centralistic network structure of existing mobile networks, the coupling of user and control plane and the strict delay requirements in the RAN. Consequently, an architecture evolution of mobile RANs with regard to their network architecture has to take place. Within the cooperation of Lucent Technologies and the University of Duisburg-Essen in the project IPonAir, funded by the German Ministry for Education and Research (Bundesministerium für Bildung und Forschung (BMBF)), and within the work carried out for this thesis, a flexible, efficient and toolsupported approach was developed that allows for an evaluation of future mobile RANs with regard to signaling performance. This approach provides decision support to the designer of future mobile networks in a very early design phase. The evaluation approach comprises a methodology for eventdriven simulation of signaling sequences, depicted in the form of Message Sequence Charts (MSCs), as well as a toolkit – both, i.e. the simulation methodology as well as the toolkit, enable an optimization as well as an assessment of future mobile RANs with regard to signaling performance as well as a comparison with the UMTS R99 as a reference architecture. In the thesis on hand, the above mentioned evaluation approach is presented in detail. Moreover, the approach is applied to potential evolution scenarios of mobile RANs. On the one hand these RAN evolution scenarios are optimized with regard to signaling performance. On the other hand the RAN evolution scenarios are compared to the UMTS R99 reference architecture with regard to their signaling performance behavior.