A flexible UMTS/WLAN architecture for improved network performance

Current trends in cellular telecommunications suggest the incorporation of Wireless Local Area Networks (WLANs) as supplementary access technologies into 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. Many proposals suggest that all active connections be handled through the same access network technology. However, this is not believed to be efficient in a heterogeneous environment. Therefore, a mechanism that allows each connection of a terminal to be served by different radio access technology is introduced. Based on a tight coupling architecture for interworking between Universal Mobile Telecommunications System (UMTS) and WLANs, the proposed scheme combines a sophisticated decision mechanism with flexible connection management in a way that ensures seamless service continuity during handover. The performance of the system is evaluated using a detailed simulation model and compared against existing architectures. Simulation results indicate an improvement in parameters such as connection and handover blocking probabilities, which justifies the enhancement in the overall usage of network resources when connections are handled separately.