PRACTICAL EXPERIENCES WITH AN IMS-AWARE LOCATION SERVICE ENABLER ON TOP OF AN EXPERIMENTAL OPEN SOURCE IMS CORE IMPLEMENTATION

Abstract

The 3GPP IP Multimedia Subsystem (IMS) is currently expected to provide the basic architecture frame-work for the Next Generation Network which will bridge the traditional divide between circuit-switched and packet-switched networks and consolidate both sides into one single network for all services. There-fore, the imminent commercial roll-out of IMS will have immense impact both for the migration of the core network as well as the integration of future mobile services and applications. This paper presents an OpenSER-based experimental testbed which has been designed as a minimal standard-compliant IMS core network. We discuss major practical requirements and describe our implementation of this “IMS in a bot-tle” approach. Furthermore, we introduce a terminal-based native IMS location service enabler. We argue that physical location data can be regarded as a type of presence information and propose an architecture which reuses a large part of the IMS presence infra-structure by applying presence mechanisms, like noti-fication handling, access control and privacy management, to location data. We demonstrate that the reali-zation of this service can be integrated efficiently into the IMS core environment, and pre-sent initial evaluation results for the joint demonstrator. Finally, important current and future challenges including migration, interworking, charging, Quality-of-Service, identity management, security, and regulatory as-pects, are discussed in detail, thus ending up with an up-to-date research agenda.