HCRAS: A novel hybrid internetworking architecture between WLAN and UMTS cellular networks

The seamless internetworking among various communication networks is in demand to provide anywhere, anytime connectivity with high data rate and enhanced service quality. In this paper, we propose a novel internetworking architecture between WLAN and UMTS cellular networks, hybrid coupling with radio access system (HCRAS), based on IPv6, mobile IP, and fast hand off techniques. Inheriting loose coupling internetworking techniques, HCRAS utilizes IEEE 802.16 standard air interface to set up direct wireless communication between base stations in UMTS cellular networks and local WLAN. In particular, we propose two new algorithms for intersystem communications and vertical handoff management in HCRAS system. The HCRAS can dynamically distribute traffic among the internetworking networks and reduce signaling cost and hand off latency significantly. Through mathematical analysis and numerical results, it is shown that HCRAS outperforms the tight-coupling and loose-coupling in various scenarios in terms of system routing efficiency, signaling cost, and handoff cost.