A QoS-Based Vertical Handoff Scheme for Interworking of WLAN and WiMAX

In this paper, we investigate the issue of vertical handoffs in heterogeneous wireless networks. A QoS-based vertical handoff scheme for WLAN and WiMAX interworking networks is proposed with aim to provide always best service to users. We also present a simple, yet efficient method to estimate the available bandwidth in WLAN and WiMAX networks to evaluate the real-time status of the overlay networks and make a handoff decision based on the information. By our proposal, a handoff process will not only be triggered by unaccepted signal strength but also by unsatisfied QoS parameters. Simulation results show that the proposed scheme can keep stations always be best connected with their QoS requirements met.