Flow based 3G/WLAN vertical handover scheme using MIH model

Vertical handover is to change the local interface or the access network of mobile node in the middle of communications. IEEE 802.21 Media Independent Handover (MIH) model can provides mobile nodes with necessary information for handover. This paper proposes a MIH vertical handover model which is consists of event messages, vertical handover procedure, and handover decision algorithm for 3G/WLAN vertical handover. In the proposed model, 3G base station, Wi-Fi WLAN access point, and vertical handover decision agent (VHDA) exchange event messages each other. VHDA finally decides the vertical handover for each flow according to our decision algorithm and sends the result to the mobile node. The flow based vertical handover decision algorithm is based on flow quality and cost functions. This paper evaluates the proposed algorithm through simulation experiments. The simulation results show that our algorithm may increases network efficiency.