Hybrid Coupling Scheme for UMTS and Wireless LAN Interworking

We propose a hybrid coupling scheme to connect UMTS and WLAN networks. Under the tightcoupled system, users of WLAN can also use the services of UMTS with guaranteed QoS and seamless mobility, but it is a problem that the capacity of UMTS core network nodes is not enough to accommodate the bulky data traffic from WLAN, since the core network nodes are designed to handle circuit voice calls or short packets. The proposed coupling scheme differentiates the data paths according to the type of the traffic and can accommodate traffic from WLAN efficiently with guaranteed QoS and seamless mobility. We compare the handover procedures of coupling strategies and analyze the signaling costs during vertical handover. In case of the UMTS and the WLAN are coupled according to the proposed way, it is shown that the handover latency and packet loss decrease.