A new architecture for 3G and WLAN integration and inter-system handover management

WLAN has strong potential to provide a perfect broadband complement to the 3G wireless systems. This has raised much interest in their integration. In this paper, a novel architecture using the Network Inter-operating Agent (NIA), and Integration Gateway (IG) is proposed to integrate the 3G systems and WLANs of various providers that may not necessarily have direct service level agreement (SLA) among them. The proposed architecture is scalable as it eliminates the need for the creation of bilateral SLA among the 3G and WLAN operators. In addition, intersystem handover (ISHO) protocols using the concept of the dynamic boundary area is proposed to support seamless roaming between 3G and WLAN. The dynamic boundary area is determined based on the speed of the user and WLAN cell size. The ISHO procedures are initiated when a mobile user enters the boundary area of the WLAN and are completed before the user leaves the coverage area of the serving WLAN. This ensures that the roaming from WLAN to 3G is transparent to the applications. The performance evaluation shows that the proposed boundary area based ISHO algorithm outperforms the existing 3G/WLAN ISHO algorithms.