Proposal and Performance Evaluation of Novel Architectures for the Provision of Optimal Connectivity and Services in Next Generation Mobile Network Environments

Abstract. Current trends in mobile telecommunications suggest the use of WLANs or WMANs as supplementary access technologies to the existing cellular infrastructure. Overlay network architectures are expected to improve both service provision and resource utilization under the condition that sophisticated architectural options are followed. In this thesis, two different ways to combine wireless and cellular networks are presented. The first one is a new tight-coupled WLAN/UMTS architecture that offers flexible connection management and seamless handover. The proposed solution is described analytically on both protocol and signal basis. Moreover, its performance is measured with the help of a theoretical and a simulation model built for this purpose. The second architecture concerns the interworking of wireless and cellular networks with the aid of the IEEE 802.21 protocol. The potential of this protocol to support seamless handover is examined based on the description of a signaling exchange in a WiMAX to GPRS handover case