Seamless continuity of PS-services in WLAN/3G interworking

The seamless continuity of services between 3G networks and WLANs will give users the feeling of a common environment towards the wireless technology. Three main aspects must be considered to obtain seamless continuity: an enabling interworking architecture, fast inter-system handovers (they must be fast enough in terms of human senses), and, in the case of real-time services, a similar quality of service (QoS) in both networks. This paper focuses on the two first issues. It presents an interworking architecture based on a 3G core-level integration of the WLANs. The GPRS network is available all the time forming a primary network, and WLANs are used as a complement when they are available. The switching times between networks are very low and the transitions are lossless. Our proposal does not disrupt with the current 3GPP standardization efforts making it viable in a medium time frame. This paper presents an overview of the architecture, describes the relevant events in the switching process (where the authentication and authorization procedures have an important role), and gives simulated values for the switching times.