Service Continuity across Heterogeneous Networks

Abstract

Nowadays, most mobile phones are equipped with multiple wireless access technologies, which allow the user to maintain connections while moving across networks (e.g. having a telephony service in GSM while moving to a WLAN area). The IEEE 802.21 Media Independent Handover (MIH) Services is a standard aiming at facilitating handover between these heterogeneous networks. In the current situation, in order for the mobile device to detect other wireless access network (e.g. WLAN), the user has to keep the WLAN interface continuously on and this will cause battery drain. With IEEE 802.21, the mobile device will have continuous access to the MIH function via a Service Access Point (SAP) on the GSM network and can hence receive information about the availability of the WLAN hot spot. The WLAN interface can then be turned on and the connection can be established.Unfortunately, the standard only provides the information for network connectivity but is incapable of supporting service continuity. More specifically, the standard does not enable the user to seamlessly change from GSM telephony to IP telephony when entering a WLAN hotspot.To remedy the situation this thesis has analysed future mobile scenarios and proposes a mobile service architecture, which enhances the availability of services at the same time as service continuity is ensured. The necessary functional entities both on the network and terminal side are identified and described. The thesis has also conducted thorough analysis and realisation of the two main elements of the mobile service architecture, namely Service Continuity and Service Discovery.To realise Service Continuity it is proposed to extend the functionality of the IEEE Media Independent Handover (MIH). More specifically, it is proposed to extend the information database with service information and to include service information in the information exchange between the mobile client and the MIH.Regarding Service Discovery it is an innovative discovery scheme capable of handling the following characteristics:Similar services with different names in different languagesDifferent services with similar namesPartially similar servicesNo restriction regarding the name lengthAnybody can introduce anything as a service anytimeTo verify the validation of the three proposed items:The future mobile service architectureThe Service ContinuityThe Service Discoverypartial but sufficient implementations have been carried out. Consequently, it is possible to conclude that the three proposed items are both sound and feasible.