A seamless handoff scheme for UMTS-WLAN interworking

In this paper, we present a practical UMTS-WLAN interworking architecture based on 3GPP standards, and propose a seamless handoff scheme that guarantees low delay and low packet loss during UMTS-WLAN handoff. For low handoff delay, the proposed handoff scheme performs pre-registration and pre-authentication processes before the layer 2 handoff. Moreover, it uses packet buffering and forwarding functions in order to reduce packet loss during the handoff period. Numerical and simulation results show that the proposed scheme performs well with respect to signaling cost, handoff delay, and packet loss compared with conventional schemes.