关键词: 异构无线网络, 垂直切换, 触发机制, 介质独立切换, 可用数据速率估计

Abstract: For the issue that traditional vertical handover trigger mechanism cannot guarantee to provide the real-time highest data rate, a method which can make the best of network resources and can effectively avoid unnecessary handover was proposed. This paper introduced IEEE802.21 Media Independent Handover (MIH) standard，using Media Independent Information Service (MIIS) provided by MIH Function (MIHF) to get the parameters of candidate Wireless LAN (WLAN) which can cover the mobile terminal, calculate the maximum available data rate of the candidate WLAN using the acquired parameters, and compare the maximum available data rate of WLAN with 3G networks to make handover decision. And when higher data rate WLAN was detected, handover to it could be made timely. If the mobile terminal moved out of the WLAN coverage, handover back to 3G network was made. The simulation results show that the proposed algorithm can make more full use of network resources and avoid unnecessary handover effectively compared to traditional vertical handoff trigger mechanism.

Key words: heterogeneous wireless network, vertical handover, trigger mechanism, Media Independent Handover (MIH), available data rate estimation