Study And Implementation Of Handoff Technology In 3g-wlan Interworked Networks

The 3rd generation mobile communication system has a high degree of security and perfect billing management function. It can also provide large coverage and nearly universal roaming too. However, its cost of deployment is quite high. WLAN can provide higher data rates with lower cost than 3G, but its security mechanism is very fragile. So, the integration of 3G and WLAN can complement each other very well. How to ensure that mobile terminal can access heterogeneous networks adaptively and safely, how to guarantee QoS when mobile terminal handoffs in heterogeneous networks are hot issues in the research field. This paper focuses on the secure Access of 3G-WLAN and seamless handoff as follows:First, the available integration architecture of 3G and WLAN supports mobility poorly. This paper proposes a handoff technology based on Mobile IP to achieve adaptive handoff control.Second, based on the study of traditional switching technology, this paper design a location-based self-adaptive vertical handoff algorithms.design a 3G-WLAN integration fast smooth vertical handoff scheme.Third, to verify the proposed handoff scheme, this paper combines it with the integrated authentication to construct a secure access platform for integration network. And an experiment platform is built, and the secure access platform is tested. The testing result shows that the secure access platform attains the design goal, it can achieve the proper safety rapid access and switching, reduce the handover latency, the mobile terminals can move freely in the 3G-WLAN integrated networks with higher communication quality.