A Tiered Mobility Management Solution for Cellular/WLAN Integrated Networks with Low Handoff Delay

Abstract. Demand for the Internet services through GPRS/3G networks is proliferating day-by-day. But low bit rate puts constraints on multimedia or mobile business services. In contrast, Wireless Local Area Networks (WLANs) provide high bit rate with low deployment cost. Therefore, integration of these two complementary systems would be the focus of next generation wireless networks. However mobility and handoff management become the key issues for such integration. If a cellular operator deploys as Operator's IP network (OIN), it will be connected to GPRS at Gi interface and to the Internet through firewall. Alternatively, the Internet can be connected directly at Gi interface and OIN can be connected to the Internet. These connection mechanisms restrict on scalability due to large packet forwarding delay. In this paper, we propose a new way to integrate GPRS/UMTS, OIN and the Internet for better scalability and smaller packet delay. We deploy one gateway for users of cellular (GPRS/UMTS) and WLAN host. The gateway is in OIN and is connected directly with GGSN at Gi interface. The home agent functionalities are distributed in two level hierarchies within the OIN to reduce the packet and handoff delay. The proposed architecture would be useful for large network size